The harsh reality could be that they are not happy with the op and their performance, and in a cowardly fashion not expressing it honestly to them. That could be the case and it could be worth introspecting on that.

In this case it has nothing to do with the OPs performance and everything to do with their own poor leadership being reflected back to them.

Note the verbiage: he was told he was "the best engineer". That might well be true even though nobody could stand him as a person.

Considering how nobody is lifting a finger to help him, I reckon nobody else particularly enjoyed having him around, but couldn't get rid of him because of their reliance on his technical prowess.

Yeah I think this is probably true. Rightly or wrongly they don't see him as a team player, but were required to keep him on because of his technical prowess.

It sounds like they're managing him out and he'll soon be on a PIP.