They have not in any way, shape, or form said that 4E was a mistake. And anyone who says so is just flat wrong.
As to the last part, of course they're trying to win back some of the fanbase that gravitated towards Pathfinder. It's a competitive market...a competitive niche market. There are only so many people that buy RPG's, and yeah, WotC would love if every single one of them also bought the 1E Reprints, the 3.5E Reprints, and 5E...just as I'm sure Paizo would love if every single one also bought Pathfinder. The truth is, WotC is trying to win back each and every person that ever played any edition of D&D, and shooting for new players to boot. Every RPG game company does the same thing.![]()
They are trying to win back the - large - part of their former player base they drove away to Pathfinder with their insulting "3.X sucks, 4E rules" advertising campaign and their "we'll stop offering PDFs of earlier editions so you have to buy our new edition" decision. It's a good idea, but it may be too late already.