Oh, hero worship...

Bruce was part of the mixed martial arts philosophy, in my opinion. I think he probably would have been involved in it in some way. If only as a commentator or trainer, I think he would have had a hand in it.
The thing I wonder about Bruce is the same thing I wonder about Jimi Hendrix; if he would have stayed around longer, would he have captured as much interest from people? There seems to be a degree of tragedy to the interest around both of these guys. Hendrix did a lot for the way rock guitarists operated in a band, but he wasn't the only one. Similarly, Bruce mixed is Wing Chun training with Aikido and Ju-Jutsu and had the whole Jeet Kun Do philosophy (which... if you think about it... is a little arrogant - like he's the only one that wanted to do things that worked). What he was doing wasn't that much of a departure from where things have gone in the MMA world. Both of these guys helped and things probably would be like they are now without them, but they definitely left their mark on how things progressed specifically. I only find it curious because it's interesting how people react to these two characters.
I love how people explore these insane hypotheticals about if Bruce could handle it or whatever. While training has improved in general, it's through the efforts of guys like Bruce. It's like saying General Choi couldn't handle modern TKD training or that Miyamoto Musashi couldn't handle the skill of the advanced Kendo people and would get owned hourly now. *yawn* It just sounds like armchair blowhards pontificating about things that are useless. No new understanding arises from these pursuits, it's just mental mas... erm, you know what I mean. Anyway, leave that for the philosophy majors.

Bruce helped. Enough said.