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.
That reminds me, why do Cincinnati and Cleveland get professional sports teams and Columbus doesn't? It's both a bigger city and metro area.
In both transportation infrastructure and settlement history, Columbus resembles nothing more than a Sun Belt city; it became prominent relatively recently. Sun Belt cities in general received teams through expansion or relocation late in the 20th century, but Columbus is relatively close to Cleveland and Cincinnati and Columbus residents generally have pre-existing attachments to teams from those cities, so Columbus has generally not been considered. The exceptions are the NHL, which has not historically had much of a presence in Ohio (there was a short-lived Cleveland team that folded in the '70s), and MLS, which was created in the '90s.
As BuckeyeNut mentioned, the other factor is that Ohio State dominates the attentions of Columbus. Professional sports has to play second fiddle.
Don't forget city lines too
Cleveland is very clean with only one small enclave on the lakeshore and Cincinatti is a bit ugly but its relatively compact besides a few weird tendrils and enclaves.
Columbus is a monstrosity.
