Not a chance. I've said this before, but I feel viewing the PHB as a "living" source is unprofessional in the extreme. If they want to release an Unearthed Arcana (1E or 3.5E style) book of expansions, options, etc., I'm fine with that. They're also welcome to fix typos in future printings. If I compare the PHB I bought in 2014 to a 5E PHB bought in 2020, I expect the rules to be exactly the same. If they aren't, it's a different edition.
Just to be clear, I'm playing 5E. If they "stealth" a 5.1 (or whatever), I'm done. I'll not be buying any more books. In fact, I'd really like to get more information about what Mearls meant by his comment. If it means he's open to doing something like the 3.5 Polymorph "errata", then I'll cancel my orders for the MM and DMG, right now, and avoid being annoyed about dealing with that same sort of unprofessional attitude that frustrated me in late 3.5.
What do I mean by "unprofessional"? I mean anyone who does it should not be producing product for profit. It is treating it like a hobby (not ours, theirs). The PHB has only been out for a month. If you have so little confidence in your product, at this point, stop doing it.
That said, I think 5E is an amazing system, as it is. It certainly speaks well of the design/development talents involved. The idea of reprinting the PHB would reflect equally poorly on the business mindset and professionalism of those involved.
As a final note: I don't know that Mearls meant that they're going to reprint the PHB. I could, just as easily, read the OP paraphrase as an invitation to "expanding" the game via a UA type of product, as I suggested in the first paragraph. I'm intentionally looking at this through a poor light because I feel very strongly that 3.5 "errata" was botched in a very big way, and don't want to see the door open to that again.