I don't find trail runners to be any more or less egotistical than road runners, but I will say that there is more of the attitude of "finishing is the goal" where just the challenge of completion is seen as impressive. But you get it on the roads with the marathon too (and sometimes even with the half, the 10k, and even the 5k). I think that's the attitude you're referring to, and yes, that does exist.
Also, I'll agree that the road are far more competitive, but as someone who has done a fair degree of trail racing, I will also add that it's easy to underestimate how difficult it can be to run fast. I'm a mid 15 minute 5k, low 32 minute 10k guy, with a history of decent mileage on trails. I did a trail half marathon that went down, up, then back down a ski slope, and I thought I could just waltz in and clean up... the previous winners had only averaged 8:00 miles or so. I went two years ago and was runner up, and was wiped for the next week or two, came back this year and won, but both years only managed a little under 7:45 pace. The paces don't sound that fast, but on that terrain and for that distance, it catches up, especially on technical tracks.