It is if they want to bet on the value of bitcoin. Why use some hardware for 40-60 days to mine some coin which may or may not be worth $1500 when you could sell immediately for that amount? Sure you can mine for longer, but I'd bet they have more stable returns by investing profit from sales back into the business for fast/cheaper manufacturing, expanding their area of operations, etc.

Pretty sure they do.

https://www.reddit.com/r/BitcoinMining/comments/7jg14f/one_o...

"During the gold rush its a good time to be in the pick and shovel business" - Mark Twain

the same analogy applies here, BitCoin mining is quite profitable, however hardware business is more reliable and in demand.

Yes, and they operate a decent amount of mining farms. However mining comes with a certain risk (eg. Bitcoin could crash) which is eliminated when selling the hardware right away. They can also manufacture hardware a lot faster than they can deploy data centers.