I thought the two weekend thing was stupid from the beginning. I was shocked how well they did with the lineups, but even then they still didn't sell out either weekend. I'm not surprised in the least that July is selling worse, since like it or not, none of the headliners have been relevant this millennium.
I definitely think that they would go for a huge add or two rather than scrap the weekend. They'd also probably do better to just put it on at a loss, since most festivals lose money their first couple years.
Honestly I'm pretty excited to party at a half empty gorge with a whole lot less teeny boppers than normal.
I would say it's extremely unlikely that they cancel July but it would not be unheard of. I'm not going to pretend to know the logistics of Sasquatch's money situation but there is certainly a point where it doesn't make economic sense to hold the festival. This isn't some show in a bar where it's no big deal if the place is half full. This is an event that involves millions of dollars.
I think ticket sales would have to be catastrophically low to justify it (below 5,000 or something) but saying it would never happen is incorrect.