Actually, I'm not convinced. I suspect a Pathfinder "second edition" will actually be a lot more like PF 1.1 than 2.0. There may well be another raft of minor tweaks to the system, and very likely a reorganisation of material (so that some of the "big eleven" core classes get demoted in favour of some of the new classes that have been developed since), but I would be very surprised to see wholesale changes to the underlying rules - it'll be much more a "3.85e" than a "4e" or "5e".
The major reason for this is simple: with the OGL out there and most of the rules already available for free, the scope for making big changes to the rules is actually quite small - whatever they do is likely to be controversial and split the market. But if all they do is a massive errata drop, coupled with a re-org to bring all the most-used items under a single set of covers, they should be able to get a lot of people to re-buy the books (if only to replace core rulebooks that are several years old, and well used, by then).
And bear in mind that if the core of Paizo's business is subscriptions, and especially subscriptions to the Adventure Path product, that frees them to not have to worry (too much) about the content of a new edition - to have it be successful enough they don't need to find new subscribers, they just need to make sure they don't cause their existing subscribers to cancel.
(That said, there does exist the possibility that someone will come up with a new and revolutionary mechanic, one good enough to render the existing SRD/OGL material obselete. In which case, PF 2.0 would look rather different. But I don't see that as very likely - it really would need to be spectacular to cause everyone to shift; anything less would just split the market.)