Exactly: it is very wrong to think PhD are useless because you won't use what you did during your PhD. This is stupid on two accounts: even if you do an academic career, what you did during your PhD is rarely what you will do later, and PhD teaches you many other things.

I only realized it afterwards, but many people are simply incapable of working by themselves without being given precise instruction: PhD teaches you that in some way (of course, there is a selection bias). It also trains you to communicate to other, which is a very valuable skill. You are also used to being criticized on somehow objective criterion: few people are able to take critics in any other way than personal. Finally, you almost always learn tenacity.

For me, saying that PhD is a bubble because there are few academics positions is like saying being an entrepreneur is a bubble because so few people become very rich. Even failure teach you a lot (where failure would be defined as not becoming an academic in the PhD case).