Subjective, sure. To the point of being meaningless, I don't think so.
That's the point, because it's subjective there's no guarantee people are going to share what you value, which means that while you can certainly persuade people to do things which hold subjective value to others, ethically I think coercion of any type is out of the question for anything that does not give objective value to the society.
That's true even in today's society, and unless "post scarcity" also implies "cure for all diseases" I think the value of different activities isn't quite arbitrary.
This assumes everyone who is technically eligible would wants to become a Doctor, or that there were room for everyone to be doctors or other high-value service professionals. Obviously there are still going to be important service jobs even in a post scarcity society so long as we ourselves lack the capacity to understand and create intelligent agents with cognitive capabilities similar to our own. But in such a situation are we realistically going to say the entire population MUST hold a job that provides objective value? Isn't there such a thing as TOO MUCH redundancy?
If we require people to hold jobs that provide others with only subjective value how do we make that sort of a system equitable and accessible to all? If we're just rating people's ability to satisfy the meaningless but pleasing desires, how do we truly rate, measure or rank that? Because if we're going to coerce compliance from the greater society we owe it to them to guarantee that their compliance in this system will make each and every individual equally happier as fairly as possible. Right now I don't think humans know enough about themselves to truly do something like that.
No, it doesn't. The value of slashdotting, even its value for myself alone, varies based on mood, how ill I'm feeling, weather, other things going on in my life. And that's not including value to other people...
Maybe it does for you, okay, bad example. My point was the value you get from slashdotting (outside of the occasional insightful/informative/funny posts which have slight chance of altering your perception by introducing new information into your mind) is still equally subjective. Yes, factors in your life influence your specific enjoyment from it. However the point is that no amount of these factors changes the fundamentally that the satisfaction you get is based on the unique configuration of your person and isn't actually tied to you doing anything substantially productive, at least no more or less productive than just spending an hour or so a day checking the news anywhere else.
And the point is that it's these myriad of factors which created psychologically the mechanism that gives you pleasure from reading slashdot or whatever other tech news sites you go to. This means that if you had not grown up as you, you wouldn't possibly like slashdot at all. This MATTERS when it comes to job assignments. This is what I meant about subjectivity, are we going to force people to post on slashdot because you and I enjoy it? Even if THEY hate it? How would we compensate those people to ensure the pain of their having to come post on slashdot was somehow reimbursed through their own equally subjective ways? How do you maintain that kind of an exchange?
Now, you can say that making games and making art has value to more people than just you and while this is tempting to use as a scale to measure desires against one another I am entirely unconvinced it is a fair way. If we are at the point where the bulk of the population cannot do productive work: Doctoring (and related medical professions), Lawyering (and related legal professions), Spying, Soldiering, Diplomacy, Research, and Engineering. and that this leaves them with a handicap where, for whatever reason, since we have to ensure they ALL GO DO SOME WORK EACH DAY we must put them to work doing things to enrich the happiness of the general population.
However, if we have to deal with forces of social jealousy so strong that we must force everyone to work, even if they hate it, every day, to keep our social cohesion going, then by creating a track of subjective work where everyone's aware that they're just doing busy-work to make other people happy then that's only going to transform that jealousy and make it so that the people whose desires were never fairly met by this system (remember, if you're optimizing for value to others that means you're not allowing a certain segment of the population to access to their possibly much more private, intimate desires, and leaving them out of the job rotation entirely. They'll always be workers and never be the one being satisfied by workers.) become the resentful, angry, disgruntled ones instead of the people who already work in productive jobs.
Of course, I question very much that we truly have enough people with a punitive/moralistic streak we'd have to force the entire civilization to work.