Probably the one type of PHEV that should survive is basically a BEV with builtin backup generator. One that's not necessarily powerful enough to drive you directly at full speed, but enough to basically eliminate range limitation of a (cheaper and smaller) battery by continuously charging it when needed. Maybe this 'backup generator' can even be made as a removable option.

I'm thinking of a semi-rural use case, when your typical daily trip is 20-50 km, but the charging infrastructure is poor and occasionally you do need to drive 200-300 km in winter.

Your phrasing implies this causes extra weight gain - just to illustrate, the new Prius is about 1.4t (while having decent PHEV range), while the ID4 (a similar sized EV) is 2t.