Why didn't Interdictor-class Star Destroyer see much use?

Question

In Star Wars, hyperspace is the main way of travel. It's used by the Rebel Alliance both as a way to attack and to escape.

Quite understandably, the Empire created Interdictor-class Star Destroyers. Those starships where made with the sole purpose of preventing other starships to go into hyperspace.

But even though those ships exist, they barely saw any use at all, especially in battles where their presence would have changed the outcome of the war.

The most damning example that come to mind would be the Battle of Scarif. At that point, the Empire knew that a fatal weakness existed in the Death Star. So when the Rebels attacked Scarif, where the Death Star's plan was stored, it was pretty obvious what they were aiming for. So the Empire sent a massive amount of reinforcements, which lead to the rebels getting decimated. But a Corvette still manage to escape and enter hyperspace.

All the Empire needed was one Interdictor, and the rebels would have never had a chance to win, because the plans would have never left Scarif.

Obviously, the easy answer would be that there wasn't any Interdictor available close enough to the battle to make it in time. Which would raise another question, why was such a vital ship, that can completely corner an enemy and cut off their only escape route, not a mandatory part of any and all fleets?

Why were the Interdictor-class ships, which provided an incredible tactical advantage, almost never used?

Answer 1

In canon, nearly every appearance of the Imperial Interdictor is followed by some kind of failure.

• In Tarkin, set in 14 BBY, a prototype Interdictor is used in an attempt to stop rebels from fleeing with Grand Moff Tarkin's personal corvette, but instead pulls a small fleet out of hyperspace. It is sent back to the Corellian Engineering Corporation due to its many operational issues.
• In the Star Wars Rebels episode "Stealth Strike," set in 4 BBY, one commanded by Brom Titus manages to pull a CR90 Corvette out of hyperspace, but is later destroyed due to two people infiltrating it in stormtrooper disguises.
• In a later Star Wars Rebels episode, "Zero Hour," set in 3 BBY, two are used in the Battle of Atollon to prevent the rebel fleet from escaping. One is destroyed via Commander Jun Sato's ramming maneuver, and another is incapacitated when Ezra Bridger and Clan Wren destroyed its gravity well projectors.
• By 0 BBY, when the novel Heir to the Jedi is set, the Immobilizer 418 cruiser was discontinued by the Empire due to its vulnerabilities.

This track record is evidence enough to show why the Interdictor didn't see much us. It was easily destroyed and inconsistent in its ability.

Answer 2

I'd just simply say costs its probably much easier & cheaper to build several regular or older versions then the near especially if it's not fully tested or has a flaw that hasn't been worked out. Take the real life example during World War II it was easier to build destroyers & later liberty ships on the quick then to build the normal troop transports & the big bad battleships for protecting fleets. Why do you think there are no battleships made today but we still make destroyers and most other ships to protect fleets & aircraft carriers or transport supplies & troops.

As DavidW felt I needed to give a bit more evidence to my opinion or observation I had to edit & add to my point. In the series Rebel towards the end Tarkin calls Thrawn back to defend the Thrawns new tie fighter project against that of the Star Destroyer stardust project. It also is mentioned in the movie Rogue where the funding & delays in the stardust/ death star project have made the emperor & Tarkin question continuing the project. One of the points mentioned is cost & delays to the construction of the deathstar & why Rogue's father is forced back into the project which leads to him building in the flaw that is later exploited. Even in real life there are people who feel that there really is no need to worry about cost for projects & yet there is always a point were costs come into play. There are other points in the Star wars universal not just limited to movies or shows but even in print or online media where it seems there is endless money time & resources to the empire & yet where even the emperor wonders about costs & wonders if something else might be better.

There are times where being able to mass produce something cheater even with limited purpose can be better then having an endless budget & producing only a few high tech type stuff. Many say one of the key points to Allies winning WW2 was the liberty ship which could be maded easily & quickly at one point several per day & using them to ship troops & supplies to Britain helping keep them in the fight. We were able to produce liberty ships faster then they could be sunk by u-boats. Thrawns tie defender fighter is being created on Ezra's planet & is shut down by Kanaan's sacrifice & this leads to Thrawn having to try to keep the project alive by talking to the emperor so Thrawn can get the funding to rebuild & start the factories back up unfortunately for thrawn the emporer ends up giving the rebels the victory & see's it as not worth it so the money goes to the deathstar. I forget which movie it was but again this comes up again after I think the first deathstar is destroyed & the emperor says that for the time & cost of one deathstar he could have had a million tie defenders & wiped out the rebels. I can only go by what i've seen & read in my limited travels through the star wars universe as to answer your question. In my last point you could build two or three destroyers for the same price in time resources & funding as you could build the bigger stronger better equipped better armored battleships.

As such that is why many these days including the US no longer make Battleships & instead make more faster frigates & destroyers to serve the purpose battleships use to do which was protect the fleet & in particular the flag ships & aircraft carriers. Sorry I just remember another point where in several movies & in the series Rebels the Rebels admit that Thrawns Tie Defender has no flaws & can't be matched by anything the rebels have let alone know about which leads to them trying to take out the factor which Kanaan helps make sure happens. This suggest that if the empire had restarted the tie defender instead of building the deathstars &/or focused on building more indictor destroyers the empire might have ended the rebels without much hassle but by focusing on other things or maybe to many projects they don't see the flaws until it's too late.

Again maybe they would have found the secret weakness in the deathstar or whatever & having a million ships faster stronger & better armed fighters then your enemy may be enough to keep them at bay, let alone be able to destroy them if they end up daring to take you on. There are always lots of "cost factors" in projects. I'll shut up now.