I think the tipping point was cheap passes
Population growth and growing popularity of off-piste skiing. And better pow skis. And web sites like this. And MCP for Snowbasin.
Even though I’ve always been an EC’er, I had dozens of trips to SLC in the early-Mid aughts. It’s a lot more crowded everywhere on pow days. I remember when Solitude was aptly named and Pow Mow was undiscovered. Lesser so Snowbasin. But news travels fast. And the facilities at SB were bound to be discovered.
Nowadays, there are a lot more locals skiing hard until 11 and then leaving for work. SLC and Ogden and Eden/Huntsville and the rest of the valley have a lot more people.
A lot more people know of the ‘off the beaten track’ areas.
As a vacationer, I rely on this: https://en.m.wikipedia.org/wiki/Predator_satiation
Good snow years/storm cycles where people can only take off so many days. Or best, sneaky late afternoon snow which piles up and the powder locusts wait until the next day.