> the problem we're talking about in this post (finding all longest matches without quadratic blowup)

Wait, what? I thought this was about finding all matches. With a minor tweak to the opening example:

We want to match `(.*a | b)` against `bbbbbabbbbb`.

I want to detect each `b` individually, and I also want to detect `bbbbba`, `bbbba`, `bbba`, `bba`, `ba`, and `a`. That's what it means to find all matches.