If we had continued on the path of free trade without "dealing in" those displaced by free trade, the pressure would have continued to grow. It certainly could have exploded in a different direction, at a different time, with a different champion, but so long as it was repressed instead of addressed it was always destined to explode.
Another plausible future is AI reshuffling the economic hierarchy. In a technological civilization the pressure valve need not be political.
As an aside, you made me curious if Trump made this constituency materially better off. Here's what Claude thinks (tl;dr: it's a wash): https://claude.ai/share/36233694-3729-4758-b2e6-c2058791ab1a