>> Who buys stuff like Bootstrap templates?

If you are a mid range developer, your per-hour consulting fee could be $200 to $300. A typical Bootstrap template for purchase is ~$30 in my experience, so effectively 10 to 15min of your time.

If you can mark up a good template that quickly (all the various pages, color combos, etc you get) -- you're really good and your bill rate should be much higher :-)

If not, it is better to purchase than waste precious time.

If you want to learn or enjoy the art, that is a separate story, and you should absolutely do it yourself.

For me, i'm primary a back-end and algo developer, so I like to find something that works well, buy it, and move onto working the engines.