> whats the goal of government education subsidies

a more educated populace is a public and civic good on its own terms. Public funding for education is maybe partially for economic returns, but is mostly because education is a necessary part of a functioning democracy and a necessary part of living a good fulfilling life

Shifting the goalposts. For most of american history a high school education was considered sufficient to be part of a functioning democracy. If a music education (or whatever) is required to be part of democracy, then everyone should have it.

So have community things where people give free lectures at the local library or whatever.