Yeah... I'm more inclined towards your view. It's hard to know for certain, but I think people would redevelop things -- after all, they already developed them once, from a significantly weaker position.

There's the possibility that I'm succumbing to the anthropic principle (if people hadn't developed these things, I wouldn't be here to remark they had), but IMO that's offset by independent reinventions of several basic technologies by civilisations starting from much less than our "post-apocalypse" civilisation would have.