I'll add that, for me, 100 bucks to play is A LOT of money. I could see myself doing it, but man, I'd rather have a smaller prize pool and be able to play several Side events too.
The problem for a lot of us who've done this for awhile is that travelling needs to be worthwhile. If I'm flying and paying for an uber and a hotel, I need to have something worth chasing, as far as prizes go.
I need to have an event with a lot of options. For people that are trained in Vintage, that play it regularly and are probably playing for the top spots, like you, great. For people like me, who live in a place where Vintage is non-existent, that have no computer to play MTGO and so play Vintage 3 times a year, it's waaaay more relevant to have a bunch of great side-events and a main event I can play without spending all my money.
(also, think what would happen if you had to pay 500 dollars for the main event, which is kinda how much it costs for me, regarding money conversions - but that's a problem I'll be one of the only ones to have, since I live in a different country)
Follow-up question: does running an event on a Sunday make this a non-starter?
No problem, but I wouldn't travel for a 1-day event and would rather prioritize those larger ones with more days to do stuff.