One of the quirks of the current system is that subsidies are pitched as decreases to what one owes in taxes. There would be more transparency (but more overhead) if everyone paid full sticker price for taxes and then the govt separately gave money to the groups whose behaviors it wanted to encourage or whose challenges it wanted to help with (or fined the ones whose behaviors it wanted to discourage). This would not be feasible either politically. But it would bring transparency and clarity.

I didn't think it's easy in practice at all. Frankly, I don't think it's politically feasible, even.

the people with money prefer being able to employ someone to essentially skip paying altogether.

But if they couldn't - because there are no exceptions and loopholes - society would be better off.