If it „did very well“ is, of course, a matter of your political views but Merkel’s coalition of the largest center right (CDU) und center left party (SPD) is exactly the reason why the political fringe on both ends of the spectrum has been radicalizing in the recent years. Merkel’s conservative voter base crumbles and she keeps on losing to the right.
The social democratic party has been losing voters, too, even more dramatically so to both the right and green/radical left. Both major parties became somewhat co-dependent clinging to their dwindling power over this country.
With all the scaremongering about a growing right wing party like the AfD, many Germans fail to realize its supporters have always been there and never grew in numbers but before Merkel had been represented by a caucus inside the most popular parties. There have been various connections inside the CDU and the “Seeheimer Kreis” in the SPD that have become marginalized during the Merkel years with her overly pragmatic and uninspired way of administering a whole country and not committing to any visible political principles.
As a famous German conservative politician of the 1970s once said: „There must never be a political party establishing itself on the right side of the CDU“ (or it‘ll be the end of its dominating power). Exactly that, leaving room for the AfD, was one of Merkel‘s biggest mistakes and it’s going to haunt Germany‘s politics for many years to come.