Correct, but they do a lot of fab work for other companies. It's not absolutely necessary to have your own fab to be competitive unless your volumes are huge... at which point you can afford it.

Apple have $245bn on hand, so they could have a dozen $20bn fabs if they felt the need. Bezos has $180bn and no idea what to do with it.

https://www.cnbc.com/2019/01/29/apple-now-has-tk-cash-on-han...

They could, but the answer to "what should I spend $20b on" for both pretty clearly isn't "a fab where at the end of the day you might get a fraction of a percent better costs on bare dies from the vertical integration versus just buying from TSMC or whoever"

Fabs are both a commodity, and take a high capital investment. Unless you have a geopolitical reason to create one and you get .gov kickbacks to make it happen, then there's way better uses of your money.