Well, our society needs people who can reason about ethics, for example.
If society needs a thing then it has utility, if it has utility then it is marketable. That said wit snot just “does society need some number of these people” as it is about having the correct number of them.
Sure society needs (and will pay for) people who study ethics. It is a marketable skill as long as there are not enough such people, at some point you have too many and its no longer marketable.
Every nobel peace prize winner could be argued is likely an expert on ethics in a marketable position.
We need people who can create poetry and art. But capitalist market fear ethics, as it would conflict with profit maximization.
All of those are example of things that provide utility to society and are marketable. In fact I explicitly listed these as examples of marketable skills.
People buy poetry books, people buy art. It nis an example of a marketable skill.
As for poetry and art in general, the greatest artists tend to be poor and misunderstood, and in no way create their masterpiece for the market (that tends to exploit them after their death).
The fact that you think they are good doesnt mean they are good. But if they are truly good then either they dont have marketable skills (for example they suck at art, or dont know enough about business to sell their art, or some other needed skill they lack to make themselves marketable)… or they refuse to work for someone. There are plenty of jobs for artists, in the world , particularly if you are trained.
The value of the greatest artists is often really understood decades after their death.
Providing some benefit long after everyone is dead isnt helping us now. You want to do things that will be appreciated in 100 years, do that as a hobby. We have enough things we need now to not worry about a what if far intot he future.
Also for every artist that becomes well known after their death there are a million artists which provided little or no value because they were always objectively crappy.
So pursuing only marketable skills as a condition to survival is, again, a way to produce a reserve army if labour to keep wage low.
You just proved the opposite, literally everything you listed are examples of marketable skills when highly trained and not oversaturated. So umm, no.
This because the market do not know what will be valuable for the society.
You literally just made the case it does.