All a career is is an exchange of value between people. They'll certainly exist but what is valued will shift, as they have been for centuries. Basically you can't just look at what LLMs will do, but you have to also consider how that will affect the broader economy and what our response to such will be. So what happens when LLMs start to bring the value of most digital cognitive work down to something approaching $0? It will just create a large vacuum in the economy that will ultimately get filled by other things. The obvious things that will probably increase in value will be stuff done/created in the real world, creative work, and so on.

It's also quite likely that the next big era for humanity will be the space era. And that stands to create the biggest labor boom in human history. It could also happen far faster than many might expect, even moreso as there will be competition between countries, especially as those left with only terrestrial claims will see their influence relatively wane. Space jobs and industry can also, in some ways, act as a more productive Works Progress Administration [1] to compensate for any temporary economic instability that LLMs might bring along.

[1] - https://en.wikipedia.org/wiki/Works_Progress_Administration