Ohio has been trending right because aside from Greater Columbus and rural areas the state has been hemorrhaging voters. The population growth in Columbus is in largely the result of people leaving some strong-D urban areas who do not go to other states. Columbus keeps Ohio from becoming another Missouri, but it is not attracting people from outside Ohio.
The trend is OH is becoming another MS, just not yet.
lol
Anyway, what everyone else has said is mostly right. But also: a very aggressive gerrymander broke Democrats' ability to recruit anyone to anything above Mayor outside the major metro areas and Athens, which has had a debilitating effect on candidate recruitment. Columbus becoming the juggernaut for Ohio Democrats has been damning, as people from across the state resent it terribly.
In my experience, the feeling tends to be pretty mutual
