> Indeed it was a major point of pride among Go enthusiasts that computers could not play it well
It's typical for enthusiast of anything to believe their area is special. To be able to judge how feasible besting humans is a question for computer scientists / engineers anyway. You need some knowledge of Go for sure, but don't actually have to be a master Go player.
> It is extreme hindsight-bias of exactly the type the grandparent was talking about to suggest that obviously everybody knew all along that Go was very beatable by "non-real AI".
Maybe it was a surprise for you, but I was familiar with the pre-AlphaGo state of the art, and it was always clear it's just a technical problem. There's no fundamental difference between a game like Go and Chess, it's only the parameters which differ, where Go's space is exponentially larger.
> Others, like the inherent difficulty in constructing an evaluation function, seemed intractable
The branching factor is what makes the evaluation function difficult in Go and is therefore again a technical problem.
> Betting markets at the time of the AlphaGo match still had favorable odds for Sedol, even with the knowledge that Google was super-confident baked in.
This is a non-argument, betting markets are not rational.