Let’s say that the many, many people who are needed to do (relatively) unskilled labor such as restaurants, factory, retail, etc. are not needed to do those jobs anymore due to them being fully automated.
It’s relatively easier to automate those sorts of jobs, but what about the ones that require much more skill: doctors, lawyers, plumbers, electricians. These would take more time to automate compared to the more basic jobs. So when these basic jobs are all lost due to automation, but the skilled ones are remaining, what would a communist/socialist society do to solve this?
Would they force some people to learn how to do these needed jobs in case of a shortage? Would they allow the unemployed masses to survive without labor? What do you think?
This is one area where speculative fiction can do a reasonable job of opening the mind to possibilities. Iain M Banks, Alastair Reynolds, Ken MacLeod, Elizabeth Bear - just picking a few recent reads - all have sketches with some relevance to your questions, for instance.
Also worth remembering that work and “jobs” would look rather different in a communist society to the kind of things we have at present. For a start, hours can be much less, and the content of the work would be less degrading. That works wonders all by itself.
The model I like - which is different to saying if it’s likely or not - is work as sport. If you imagine a position like “economic planner”, for instance - and you might imagine that a lot of these would be needed in a communist society, and that we might struggle to automate the position away - it seems compelling to me that some people would want to do this for the challenge it would provide to them, and that more people would want to do it than there are positions.
Out of that, rather quickly, amateur leagues and tournaments with the prize being “you get to be the planner for X” arise, at least in my head.
Why would people do these things as a sport? Well, for the same reasons people do amateur sports at the moment. Fun, prestige, group belonging, etc.
Prestige is interesting to dive into, particularly as it relates to jobs like doctors. The social position of a Cuban doctor is quite different to that of a “western” one, for instance. Definitely worth digging into more.