Well problem is most of the polls are general popular opinion votes, but US presidential election is not a straight popular vote. As such the general "who majority of the nation like" doesn't really matter. Secure states are secure, so you might as well not ask their opinion and leave them out of opinion poll. Focus even on voting district levels in states the use electors to elect the electors and so on.
Problem is such polls are really hard work.... Almost no one does those and instead tries to read tea leaves out of general opinion polls. Polls which simply don't have the granularity of data to make conclusions. You need to ask "what is mood in this swing district in this swing state". After you have first added up the secure states, well with some looking of "are our old estimates of what are secure states for blue or red correct". Not that opinion wise all states aren't purple, but as far as election system results go there absolutely is blue and red states.
As I understand even in USA maybe one of two whole nation granular polls are done, with the actual amount of data to actually conclude how the actual electoral votes split. Given as said, since in some cases it isn't "you have to go down to state by state". Nope "we have to go district by district since this state has weirdo way of electing electors or adding up the totals."
Aka FPTP wasting votes in most USA states since someone thought it great idea to issue electors as state size blocks. When Constitution gives each state right to decide ways of apportioning their awarded electors.
State starts awarding 3 democrat electors and 7 Republican electors and suddenly both parties care to entice voters to try to make it 2 and 8 or 4 and 6.
Doesn't even take removing the electoral college. Just state deciding "state wide FPTP is stupid", we are going to start using something more proportional.
Even in swing states it would still work, work better. Since there would be fight over is it 5 and 5 or 6 and 4.