This is somewhat of a dual to Word for "stating the obvious?", but what would be a good word selection to say that someone's point is obvious in hindsight, but without any sort of negative connotation that the idea is trivial?
His idea to fund prevention versus treatment is [obvious in hindsight]
@pageman is on the right track, but here's how most people would phrase it:
In retrospect, his idea to fund prevention instead of treatment was a good one.
I would write "His idea to fund prevention versus treatment was prescient." Maybe loses the "obvious" connotation, though.
You could use plain or apparent.
"The value of his idea to fund prevention instead of treatment became plain."
"Patently" is a good modifier for "obvious".
patently obvious
The phrase still carries (for me) a negative connotation about the people who should have realized the point, but I think your concern was about the point itself seeming trivial.
Perhaps "vindicated by experience"?
try retrospectively:
Retrospectively, his idea to fund prevention versus treatment was good.
