The AfD has no real power in Germany. They may have swayed a few votes but in one or two legislation periods their voter base will have been quietly absorbed into the establishment (CDU and SPD) or the opposition (Greens, The Left) or the parties nobody likes (FDP).
Basically none of the other parties in the government want to even consider cooperating with them, it'll fizzle out soon enough.
Is becoming the third largest party in Germany after the 2017 federal election and getting 94 seats in the Bundestag suggestive of fizzling out? In the Netherlands, no one wants to cooperate with Wilders' Party either but in the recent election it became the second-largest party in the House of Representatives. 'Forget about it, they'll go away' is maybe the triumph of hope over experience.
I see them being this big as positive in that it forces the remaining parties to finally figure out how to properly cooperate, as the CDU/SPD is a very unlikely coalition considering the last legislation period.
The current Jamaika Coalition has basically put everyone in panic because for the first time in forever the major parties can't just vote what they want into parliament via coalition contracts.
The AfD will be reabsorbed, don't worry about that, that's how it has worked the last couple decades. And in the meanwhile they can exert some healthy pressure on the rest of the Bundestag to get a bit of fresh air in there.
It's cute how you classify the Greens as opposition, and how you describe a party that just got 10.75% of the national vote two months ago as being liked by nobody.
I haven't met anybody who likes the FDP either, but I'm conscious of that resulting from my social circle (which is heavily left-leaning). The poll results beat a single person's anecdata everytime.
Before the Nazi Party came to power, it took part on several elections: 6.4% and 3% in 1924, 2.6% in 1928, 18% in 1930, and 37% and 33% in 1932 (came 1st) and 44% in 1933.
A party doesn't come out of nowhere. It takes time. In 2013 AfD missed the 5%, but not by much. In 2017 has 13% and is the third largest party in Germany. Saying that it'll fizzle out soon is naive at best.
Basically none of the other parties in the government want to even consider cooperating with them, it'll fizzle out soon enough.