He had time and money to recover. Recall couldn't even begin until he had been in office for a year and then Walker skillfully manipulated extensions on recall certification and the scheduling of the recall election (scheduled in July after college ended for the summer so students wouldn't be around to vote, people were away from home, and his "numbers" would rebound because the memories of far too many people in Wisconsin had faded).
He needed time to lay low and stop doing things that reminded people that he was an extremist whose radical actions had prompted a recall, had many months to run a long lasting media ad blitz to promote himself with lies and propaganda, and organize a whole lot of help from RW talk radio which saturates the state and our traditional media that pushes Walkers' propaganda. He was also the beneficiary of tens of millions spent by dark money groups like Wisconsin Club for Growth.
And that's before the real recall campaigning even started. Before the recall election itself, our media was saturated with untruthful ads that were never scrutinized or questioned by the media that profited so handsomely from them. When it comes down to it, there is no limit to the resources Walker had at his disposal.
He "won" the recall on compliant media, piles of money, liar ads, and voters with the memory span of goldfish.
Fast forward to his Presidential campaign which started flagging after bloviating pitch-man Donald Trump announced his run and sucked all the media and oxygen from the room. His first debate performance was so poor, he might have done better not even showing up. A series of un-Walker-like bumbling and stumbling along with serial flip flopping on issues has been a boat anchor not thrown to this drowning Presidential hopeful, but seemingly grabbed by him instead of a life preserver.
In a nutshell, Walker has not been Walker and I don't know why.