Why do you think miners lived in tent and shanties rather than building nice homes?

I assume this question is about the California Gold rush of 1849. So I'm basing my answer off that, they built shanties and used tents because they knew that one day the gold in them hills would eventually be all gone because of the amount of people who had come to California in search of fortune. Thus tents and shanties were cheap and easy to put and easy to take down when the time came.

Basically the miners knew they weren't going to be there for very long.