"Islamism" isn't really a single thing. In the Islamic world you've got your caliphate restorationists, but also those whose Islamism has more in common with Christian democracy than with ISIS, plus a much broader mass of voters and parties who may have generally politically conservative Islamic mores but who also have other material concerns that will affect their political affiliations.
And then you've got Islamist identities in western countries, which take different forms based on the political context they're reacting to it in that country.
There's enough variation there that it's possible for some of them to be in structural/cyclical decline whilst others are resilient or growing forces.
The OP was referring primarily to Salafi jihadists that we are all familiar with from the 1990s and 2000s:
And to answer the OP, not anytime soon, if this article from last summer is of any indication:
Report: Taliban allowing Al Qaeda training camps and providing support, despite U.S. agreement to cut all ties
