Regarding job movement, MT actually has a number of high tech companies per city, but it's a much smaller handful. Using Helena as an example (valley population ~80k), we have: Northrup Grumman, the State Agencies, SoFi, TSI&T, Boeing, Tempest (they work on KOA.com), Blue Cross Blue Shield, etc. Layoffs are not as usual here as we have a significant talent shortage. For instance I believe SoFi has ~200 devs in Helena when they would like 400 devs -- hiring being the biggest barrier.
Throw in decent internet and companies which hire remotely, and you're in good shape.
That said, Bozeman is currently experiencing a housing bubble that doesn't seem to want to break (we attribute it to the older Californians who are trying to avoid taxes on the houses they sold there). Nothing like SF, but 2x-3x the rest of Montana.
The biggest downside is a lack of employment options. When the company had a huge layoff I started looking around for other jobs in the area and realized there weren't any.
I ended up taking a great job 1000 miles away in a major city. That's when I realized another downside to smaller markets - it's really hard to sell a house and house values don't change. Even though we bought a foreclosed house in 2007, the value in 2014 was unchanged. After looking at what we had spend on improvements and upkeep we would've been far better off renting a house and putting more money into savings.