Lord Mhoram
Hero
That is not realistic. If they do a "second edition" it would happen much sooner than that. Of course, they may never do one.
It came out in production form in August of 2009 so it is approaching 5 years old. If it follows the original AD&D as an "old time" example it could be around 9-10 years before 2nd edition of it happens. If it follows more modern RPG examples (Star Wars, Savage Worlds, Doctor Who, Firefly, D&D itself, etc.) it could go into a second edition at any minute. Games seem to only go 2 to 3 years before "new editions" anymore.
I know. I was posting when I wanted, and a little tongue in cheek.
But there is one thing to consider about Pathfinder and a Second edition. Almost all games that have a longer lifespan run on the rulebook/splatbook model. The understanding is that adventures don't sell is a given. The Pathfinder rules were made explicitly as a rulesystem to keep in print so they could keep selling adventures. I see thread in multiple boards of "I love Golarion, how would I play it with [System]. As long as the rules are "good enough" that their adventures and world books don't see a huge hit in sales, that likely won't be an issue.
Each year they only put out 3 big hardcovers - and so far one of those is a Bestiary or NPC book. And they put the rules up for free, very quickly on the website (unlike D&D back when), usually within a month. They have subscriptions for their different lines, so that tells them pretty much how many books they will sell, a brilliant concept if you ask me.
There is also the fact that Pathfinder was created and marketed to people who didn't want to switch to 4E in the first place, and who likely don't want to see a new edition where they have buy all new books for.
All of that combined means that the primary reason to make a new edition - flagging sales of the core books, and less sales of later rulebooks, are not as big a factor in Paizo's business model. I could realistically see another 5 or 10 years without a new edition.