This almost happened but too many crochety people in those communities who fought it because "that's not what I experienced" and yet are the same ones who let places like these languish with century old derelict buildings and complain about property taxes trying to get new ones. While I hate taxes, too, until you can get past that culture you're going to be stuck with too many districts.
If you read the historical record, places that are the results of consolidations - especially in that area (like Miami East, Vandalia-Butler, Troy, and Northridge) that occurred many years ago basically told the residents "this is what we are doing" and did it while bearing the repercussions. However, there were many other societal changes that happened which lent teeth to these mergers such as the Progressive Era and that whole "maybe our children shouldn't be working in mines" thing. So short of that happening (Again, see culture and complaints), this is always an uphill massive battle.
But to the above point, there are way too many. Ohio as a whole should adopt more county-level aspects including schools, safety services, infrastructure, etc. but as the good home rule state we are, good luck with such a shift. If more populous states can do this, Ohio certainly can.