system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] When two Jedi face a foe together, why doesn’t one just use Force manipulation while the other light saber-fights? 2-on-1 doesn’t usually end in victory, as we’ve seen so many times in battles with Darth Maul and Count Dooku.
gpt
The short, blunt version is that A) the Jedi train their people to act as lone wolves, and that's reflected in their combat doctrine and B) the Jedi Order suffers massive institutional inertia, making it hard to adjust to changes in the battlefield.

For the former, consider that the traditional mode of operation for the Jedi has them (and possibly a Padawan) rolling off alone into the unknown to act as a problem solver. They are trained to act alone, and that includes the fighting styles, which all place heavy emphasis on the individual acting alone; there's a "fencing" form, a "blocking" form, and a "power attack" form, but no "tag team" or "spear wall" form. 

For the latter, especially in the Late Republic period, the Jedi basically need to be drug kicking and screaming into any major adjustments, which they do grudgingly. They don't make any changes to their training or practices that aren't absolutely mandatory. Probably the most damning example would be Obi-Wan himself, who in spite of having multiple *first-hand* experiences of being in asymmetrical saber fights has personally adopted no tactics beyond some minor signals with his trainees; even if the Jedi as a whole stick their heads in the sand when Darth Maul took out Qui-Gon, one would think that he would have been changed by the experience. But the training methods of the Jedi at that point encouraged an extremely straight line "this is the way we do things" sort of thinking, and made adjustments difficult.