The reason the top players cannot / have not beat 1:30 is probably because of their playing style. Getting fast bots seems to deal with how you play; as far as I know, just running their as fast as you can is luck. However, if you do it the way I do, which involves rather noobish tactics, will get you some good bots a lot more consistently. So, maybe those other guys (Easton, Otto) got it with faster bots...like, say, 47. They might just not have the skill to get a faster ending. Maybe they got 42 finishes, or 43...
Whereas, I'm assuming people like Paragon and Disco probably just got 49-low 50 bots and did good finishes. But, since they probably do the start different, they get a smaller amount of fast bots, and probably just don't want to keep trying since it makes the level seem very luck dependant.
I remember when I just joined, I talked about how I got 50 bots a lot...Renem said he hated me because he couldn't get those ever. It seems that the bot is affected by how you play or what you do.