Title insurers have not had to do due diligence for decades because record keeping has gotten so reliable there is almost never a problem. The underwriters just eat whatever occasional costs arise, and title agents make bank - at least on the East Coast of the US, out West they are typically one entity but the process is the same. Solar adds an interesting new wrinkle!

You would think hopefully that having title insurance. That the title company would need to do everything for hopefully no out of pocket cost.

Mineral rights? But that's probably specialized to certain parts of the US (upper midwest, southwest, NE Appalachia).

And water rights, but mostly a west-of-the-Mississippi thing?

Yeah, those would be things they might know about, but mineral rights usually DON'T convey (in some places they do) and water rights is usually a farmland thing.

I daresay this title company will now be on the lookout for things like this!

Water rights are very common for residential properties here in Utah. I currently live in a townhome, but several of the homes I had looked at had X "shares" of water from the reservoir in the mountains a few miles away.

Title companies are like an old folks home for politically connected lawyers. They do very little, and make enough money to spackle cash over their mistakes.