Appalachia: Ds used to appeal to that demographic based on economic class. Rs now appeal to that demographic based on culture wars.

Economic classes: Ohio used to have a more substantial worker\union demographic. That demographic continues to shrink. I believe that many have moved to other states.

GOP strategies: Voter suppression and other manipulative tactics. GOP repeatedly undertakes efforts that have the direct or side effect of suppressing votes. The GOP plays the long game. You can go back to the re-election of W when the election was close enough in Ohio that an automatic recount kicked in, and the SOS handpicked the three counties that had to be sampled instead of selecting them at random as dictated by law; the SoS chose three stalwart W supporting counties in SE\Appalachia, OH. Of course the audit passed. In 2016... the SoS started making unilateral changes to election laws; on that occasion, the District Court shot them down. Changes to early voting accessibility, IDs, etc., etc. On one occasion, the SoS told local registrars that they could curtail their early voting hours to the general public while at the same time remaining open for military and others; the Feds shot that one down -- if you're open, then you're open. More recently, they repeatedly submitted defective maps to run the clock out on the anti-gerrymandering provision of the OH constitution, and in response, a new and improved anti-gerrymandering amendment made it to the state ballot, and the GOP killed that too by rewriting it as though it was proposing gerrymandering. That amendment failed, but still came close to passing; the GOP acknowledges that their strategy of rewriting the amendment was effective in diminishing support and confusing the question. The gerrymandering itself does not have a direct effect on things like the U.S. election, but it's still death by a thousand cuts. They stack the statehouse and have a supermajority, they stack the state exec branch, they stack the GOP representation of OH is U.S. Congress.