Is Borg adaptation only temporary?

Question

It seems like Borg adaptation, at least in terms of battle, is temporary. In every episode and movie I can think of, the initial attack against the Borg is effective. Unless the countless species across the galaxy are all using different weapons, including within the Federation itself.

This would also explain why Picard was able to kill the Borg on the holodeck in First Contact. The Borg didn't have time to adapt to the attack but further attacks should have led to adaptation against the bullets, surely?

Why does the initial attack work unless adaptation is only temporary? It seems to me that the Borg are attacked, adapt to whatever is attacking them, then cease to have that adaptation once the attack is over.

Answer 1

Because the borg adapt to a frequency

Star Trek shields work on a frequency, and once you know that frequency, you can alter your weapons to bypass those shields, which is why you'll often hear characters calling to 'remodulate shields'. Borg adaptation works in the exact opposite fashion, instead of having a frequency you need to bypass, they adapt to your weapon's frequency, rendering it ineffective.

The Borg can often figure out within a few shots what kind of frequency their opponent is using, and switch their shield frequencies around to counter. To get around said Borg shields, the Federation will often use 'rotating frequencies' for their phasers, but even that only works for a short time before the Borg can adapt to the rotating frequency. (Imagine phasers picking a 'password' for their frequency and it takes the Borg a few casualties to figure out that password, but once they have it, that rotating frequency becomes useless as well.)

So the reason that they "lose" their adaptation is because they don't know beforehand what kind of frequencies their opponent will be using.

Answer 2

Because they value resources over drones.

While it's true that the Borg adapt to phaser frequency, they would rather lose a few drones than waste the energy and resources to constantly have defenses up. The Borg have shown time, and time again that they don't care how many of them die, as long as they get what they want. In fact, in the Voyager episode Scorpion: Part I, they sacrifice an entire cube on a whim so that they can achieve a greater purpose. In their collective minds, having a drone killed by a phaser is less of a loss than the effort it would take to guess at the initial frequency of a phaser blast. As SpacePhoenix noted in the comments, this is even further backed up in the Voyager episode Unimatrix Zero, where the Borg show that they would rather completely destroy several cubes rather than using the time and effort that would be required to scan them for a threat.

If they cared at all about saving themselves, why not have shields that cover all phaser frequencies? They'd lose fewer drones, but that's of no importance to them. Drones are a dime a dozen.

For the Borg, having constant shields up on their drones would be the human equivalent of putting a $1000 AC unit in an ant farm and paying $200 a month to run it. It's just cheaper to lose a few, insignificant, ants. However, once they've identified the modulation of their enemies weapons, they can economically protect against it. Again, not to save their drones, but simply because it makes achieving their goal a little easier if their drones don't die so quickly.

TLDR: Saving drones is just not important enough for the Borg to remember those small details.

Answer 3

The thing is, Borg are just being economical, shields use lots of energy, they don't want to waste it by constantly holding up energy field on every ship and every individual drone.