> There will always be people not happy with the government.
> Who should they vote for? They can only go to an extreme party.
That is what extremists want you to believe. But the belief that both big parties are corrupt exists in the USA as well, and it helped Trump. The fact of the matter is, if you are unhappy with what a grand coalition does, you can still vote for the party that you agree more with to have it gain more power next time around. Only if you believe that cooperation and compromise themself are bad things, you have to vote extreme.
That is easy to observe in German politics. Yes, some people vote for the party they agree with more, but many do not. This has nothing to do with "the party is corrupt", but with "the party doesn't do what I want them to do".
> Who should they vote for? They can only go to an extreme party.
That is what extremists want you to believe. But the belief that both big parties are corrupt exists in the USA as well, and it helped Trump. The fact of the matter is, if you are unhappy with what a grand coalition does, you can still vote for the party that you agree more with to have it gain more power next time around. Only if you believe that cooperation and compromise themself are bad things, you have to vote extreme.