I live in L.A.
When you go to vote a municipal election, it is absolutely dead at the polls. I can remember many times voting in a municipal election and I was the only one at the polls voting. I can see the frustration of city officials at the abysmal turnout. Now that certainly does give MY vote a lot more leverage. But it really doesn’t make much of a difference anyways. The LA Mayor and City Council are overwhelmingly liberal in any event so I don’t see how it could get much worse than it is already.
If they really wanted to maximize voter turnout, all they need to do is schedule municipal elections in presidential and midterm election years. Currently municipal elections are scheduled in the odd years thus guaranteeing an extremely low turnout.
I suspect the only reason they don't sync the elections is that there are probably special interests who believe or possibly have found that it's easier to get a bond measure through or a proposition passed if the elections occur in off-years or during primaries or special elections.