At best they don't believe actual AI will be created and they are helping a scam.
At worst, they are actively working to make their own job redundant and when they're fired, they will own nothing of what they built. All the money from their work will go to the owners who fired them.
Except that's the case with literally every meaningful information-work job. Your goal is to obsolete yourself. If you do it well then your success becomes your calling card for your next job. Your career is a series of such jobs.
2) Even if your claim was correct, then you'd amass experience on one job (task) that you could then leverage on the next job (task). If AI became reality, all that would become irrelevant. Your middle-class self would quickly realize you're only worth as much as your lower class neighbors who swing a shovel or flip burgers for a living, all the while your upper class bosses become richer thanks to your work.
In a well functioning society improvements in economic efficiency and productivity improve the standard of living if everyone in that society. Thus if you innovate yourself out of a job you'd still benefit and would have access to any training needed for your next job.
Sadly, I am becoming increasingly convinced I do. [1]
You're falling for one simple trap. Yes, even if things are (mostly) improving for everyone, they are improving massively faster for those already rich.
On top of that, I am not even sure they are improving. Some people are paying a third or even a half of their salary just to have a place to live. I even heard the situation in some cities is that people are struggling to feed their kids and keep the heating on.