Episode III obviously doesn't show ALL the Jedi being eliminated as a result of Order 66. What I've never heard, though, is how many Jedi were in existence at the time of Order 66. Is there any definitive count as to how many of them were alive at the time of the purge and how many were victims of Order 66?
Wookieepedia indicates that less than 1% of the total number of Jedi were thought to have survived the Order 66 purge.
Although Order 66 greatly depleted the Jedi Order's ranks, with an estimated less than 100 Jedi surviving it, it was only the beginning of the Great Jedi Purge, which stretched on for years and would claim the lives of many of the survivors of the initial onslaught. Nearly all of the surviving Jedi Knights were hunted down and killed by Darth Vader, while Order 66 itself remained in effect indefinitely among the ranks of the Galactic Empire's newly-christened stormtroopers. Masters Kenobi and Yoda, like many others, chose to go into exile, on Tatooine and Dagobah respectively. There they managed to elude Imperial forces for many years, a feat few of their contemporaries could claim.
Using the estimates in Wookieepedia, (1% survival rate with 100 or so surviving) this meant there were approximately 10,000 Jedi at the start of Order 66. This number likely included masters, knights, and padawans (who were not supposedly all killed but taking in for questioning).
Unfortunately the very same article while saying approximately 100 survived, also indicates this might have been incorrect and says that perhaps 200 survived.
Being a writer, I suspect there had been no absolute numbers established so there could be as many Jedi as needed for different franchise writers to be able to write without stepping on each others work. So when one hundred was the target number, I think someone decided that might be a bit small given the size of the galaxy, the prevalence of the Force and the skill of the Jedi overall.
Personally, Order 66 felt a little contrived especially when they released the Clone Wars animation of Mace Windu on a rampage against a droid army. If one Jedi could do what he did, could Order 66 really have been as effective as portrayed or was it a case of the Jedi cutting and running because they were simply outnumbered and the Empire's spin doctors making a case for winning because the Jedi were driven underground. Watch the video and then ask yourself, where is the disconnect?
The Jedi lost a lot of abilities they and the Sith previously had. For many years they had a semi peace. In these times without war people let their guard down and become over confident. Thousands of years ago in the Jedi-Sith war they used many lost or weakened abilities such as Inhanced battle meditation and such, I see very little of these powers used through the clone war times. Throughout the entire movies and various novels comics etc many powerful Jedi comment on their senses being clouded by the dark side. Like Master Yoda and Master Windu.
This was Sidious master play.... and he pulled it off to perfection. Using his position and hiding his abilities, he became senator and used the battle of Naboo to become head of the republic then started a war and this forced the Jedi out of their usual roles as peace keepers with their strength centered. Spread them throughout the entire galaxy. Throw numerous threats their way to keep them fighting and stuck leading armies of clones against a force of droids. Jedi are not omnipresent beings all knowing and all powerful. Sith since Darth Bane have followed the rule of two, this means fighting a force of thousands so obviously sith are going to be masters of deception hiding in sight and manipulation and this years long plan by the emperor was well planned well thought and hit their weaknesses dead on. The Jedi knew something was wrong but with the entire galaxy at war they had little chance to follow leads find the Sith. The Sith used the droid army to attack and oppress hundreds of worlds forcing the Jedi to defend these helpless people.
I love the movies and can't help but feel admiration for the Emperor...waiting years, playing a good guy, manipulating Anakin, gaining more power by using that fool Jar jar well Padme was forced into hiding by another part of the Emperor's plan. The details and strength to hold a plan for years and years. How could the Jedi possibly see this? They couldn't. Maybe if the majority of the Jedi were on Coruscant instead of spread so thin, they might have held off an attack on their base and been able to arrest or kill Palpatine and convince the senators of the treacherous plan. But long before order 66 they doomed themselves and if they hadn't acted to protect the other planets they couldn't really be the jedi as thats their job their role and creed. Going to war with clones created mysteriously by a long dead Jedi? Huge mistake. And many more followed but this was a huge one.
Sorry so long but I wanted to get the point out.