I'd be curious to see an example of a dialect in which "to affect change" is more correct than "to effect change"?
Some people seem to like pushing descriptivism too far. "Somebody said it, therefore it's correct."
What basis for judgements of correctness would you suggest, if not facts about how English speakers speak English?
How about facts about what nearly all English speakers agree is the correct usage?
For correctness, it should be how educated speakers speak English. In this case, I would also settle for "how published authors write English."
So... your notions of 'correctness' in a language are determined by who can get publishing deals?
Are your notions of correctness defined by who can get publishing deals?
A majority, or at least a substantial minority? (Don't interpret common mistakes as proof of correctness. Most (all?) people who spell 'lose' as 'loose' will at least acknowledge their mistake when it's pointed it out. Nobody thinks 'loose' is actually correct in their "not prestige" dialect.)
Neither one is more correct in isolation as they mean different things.