Cordray lost because he was a Democrat running in a red state against a non-controversial Republican.
Basically this. Brown had a strong enough brand to survive, but Ohio had already become extremely hard for Democrats to win. As for when Democrats will win it again, probably not any time soon, unless they get a very lucky combination of an atrocious Republican candidate, a great Democratic candidate, and a blue wave.
I mean, if the shoe were on the other foot, Youngkin still might have been able to win by a couple of thousands of votes.
Chances of that realistically happening, because there is only 1 race every 4 years, are lower than Democrats eventually improving with voters like the ones that lives in Ohio.
For example, I see a matchup like what happened in 2017 Alabama, 2021 in Virginia or even in 2014 Colorado to be like 10-20:1. That means, if coalitions were held constant, there would be about a 50-50 chance that a Democrat would be governor of Ohio within our lifetime.
On the other hand, there are three possible scenarios.
1) Democrats are able to do better in the "New South" and the less Evangelical parts of the suburban and rural west and Ohio becomes another place like Indiana or West Virginia where Democrats generally win without contesting them. If this happens, yeah. The next Democratic Governor will be 50 years from now.
2) Democrat-friendly trends either slowdown or revert to the point that Democrats need to do better in the rust belt no matter what. This is divided into 2 scenarios-
a) Democrats find strong third-way candidates that can rebuild something that looks like the pre-2014 map, the less they have to change their policies to do this, the easier it is (for example giving up entirely on Gay Rights, Civil Rights, Women's Right, or large-scale Healthcare Reform entirely rather than just moderating on them would lose fewer votes to get more votes). In this scenario, we could see a Democrat winning there during a Republican 6-year or 10-year itch in the 2030s.
b) The Democrats never win Ohio again because either free elections are eventually cancelled or the Democratic Party goes extinct because it runs out of votes to replace the ones its losing.