Well I think part of the problem is that most of Go's target audience come from languages where nil/null are used to be meaningful. They recognize it to be "wrong", but the languages in use (e.g. Java) force them into situations where, for example, returning null to mean "this entity wasn't found" is substantially more productive than catching and processing EntityNotFoundException.

I think the Go designers wanted the language to be approachable for people who habitually use null to indicate meaningful state. Multiple return values offer a way out, while still allowing newbies the option to abuse nil. (although, sum types would be nicer)

I think on balance, getting people from the 1970s to the 1980s who otherwise would not have gone there is a positive thing. Even if it's not the ideal thing.

It's not out of the question that Go will make your suggested fixes once it acquires enough mindshare.