When I moved to Montana in 2013 there weren't a lot of opportunities here for work, and that slowed the influx to mostly those retiring. With COVID and the move to remote work it opened the door to many. You can get a sense of who's moving into the area by the kind of vehicles you see. When I first got here there were few fancy cars and trucks on the roads, but now it looks like Los Angeles out there.
Another thing was that many wealthy people had second or third homes here with no need to rent them out through Airbnb or similar, and they'd only spend a few weeks here each year. That gave this area an underpopulated feel but that has changed. Many have invested in property up here and rent out their second homes because they're not as rich as they try to make out, and more than a few decided to move here permanently so it's definitely way more crowded here than it ever was. There has been a non-stop development initiative going on for the last 3 years and the infrastructure can't keep up.
10 years ago this are became crowded for a few months each summer, but now it's all year round. For those of us that like the small town feel and moved here for that reason, it's getting to be a real pain with so many moving here.