I beg to differ. The band was around close to 20 years old and doing fine before the vending scene became what you have described.
The problem with vending is it's downside far outweighed any benefit it ever gave the band.
The problem isn't vending, really, it's the losers you describe attracted by that scene. The original vendors, like the great t-shirt artists Mikio, Phil Brown or Ed Donahue roamed the lot, sold their shirts then went to the shows. I always supported those selling to make $$ for the shows, support tours but the truth is that it eventually grew to attract too much of the bottom end of the barrel.
Toward the end, the band made it pretty clear they had enough.
But this situation is...why Eugene? why now? They build the field, they make the rules, game on and good luck players.