[krapp]

... and thus some Christians claim the six day chronology in Genesis is really a six thousand year chronology... which still doesn't square with science.

To say nothing of the fact that 2 Peter was written centuries (if not longer) after Genesis, and there's no evidence the Hebrews themselves interpreted the account that way. The existence of the Sabbath falling within a single week rather than multiple millennia suggests they interpreted the six day chronology as... six days.

And the context of that verse clearly describes time from the human perspective relative to God's promises. The author isn't making a declarative statement about the way God experiences time, but pointing out that God doesn't operate on human timescales. That God may lay plans that take a thousand years to unfold.

That particular retcon doesn't make Christians look any better, it actually makes them look even worse.