Well, that's a difficult question to answer. Peoples' perceptions vary enormously as to what they're satisfied with. Personally, I reckon if you can't consistently put 5 shots into under an inch with a factory sporter, and under half that regularly with a half decent target rifle, you've got room to improve.
Most modern rifles are easily capable of doing it. Some even guarantee it nowadays.
A good reload will improve most rifles, I dare say even transform them.
I take your point about bench versus stalk, but if it's mediocre off the bench, it is for sure it will only get worse.
We all have had 'screamers', but doing it every time takes a bit more effort.
Of course, some guns will never do it---if all fails, time for a change.