If it's important to you, then keep it, of course. Every team is different just like all code is different.

The symptoms of too many meetings is people don't attend them, work during them, complain about not getting things done, etc. If the retros are working, you shouldn't need many of them. If they're not (which sounds like OP's case), then they should be less frequent.

Demos tend to be redundant. Most of the teams I worked with know exactly what the team just built; sometimes the CEO is QA. In the bigger teams, the stakeholders might be juggling too many things to attend anyway.