There is no job that is ok to pay nothing or as good as nothing. It doesn't matter what "career".
If a job needs doing by a human at all, then that human does indeed deserve a reasonable baseline which allows them to exist and even do so with reasonable dignity.
As time goes on and jobs are done by machines, and there are fewer and fewer jobs that require a human, then the output and ownership of those machines simply should one way or another be distributed enough to have the same effect.
All they have to do to earn that is not be being a criminal right at that moment.
And this extends to people who can't do anything obviously productive too. Even a sick old grandma doing nothing but telling stories to kids for one hour a week is productive, and we have no excuse not to provide for even the ones who can't even do that.
Because even if "the Earth is a life boat", we don't exist in an environment of hardship with fixed and insufficient resources where there just isn't enough food and building material and energy to go around.
There simply is no excuse for the way we treat some people. They didn't do anything wrong enough to deserve it, and it is not forced by physical limits.
Talking about what value someone provides to earn their existence is just a way to rationalize taking advantage of others. None of this equates to "I will be forced to spend 20 years learning medicine to give my time away for free to bums!" But even if it did, why is that a bad thing exactly? Because it's what, like slavery? You mean, slavery is bad after all?