The only poll that really matters is election day.
Governance is tough enough already without starting as a minority, regional party in a nation of 340 million people. This is Trump's dilemma.
Trump is now President in modern day Goldwater Country. With basically the same approval rating from the same type of voter base, with the same view ( philosophy ) of what the Federal government's role should be. Aside, of course, from the day to day nuts and bolts of actually maintaining the orderly functions necessaryof all gov't s. Which both parties agree on, mostly. ( For all the Republican ranting, through many election cycles, how is it that we still have a DOE, EPA, et al? ).
To defeat the " demographicis and geography is destiny " problems the Republicans face, they've resorted to employing pre-1964 political tactics used in Goldwater Country for many decades. Voter suppression, gerrymandering, nativist appeals, destruction of campaign rules, court stacking, tax cuts for the well off, etc. The Trump Presidency is all about using this old pre-1964 playbook to run the country.
The polls say it doesn't work to use the playback. for actual governing, but it does work for winning enough elections to continue using it, pretty much untouched by 55 years of American changes and supposed progress.
The Dimocrats, and the DLC especially, must cringe when they see these polls. The Progressive-Populist wing must be gnashing their teeth and pulling out their hair when seeing them, as well.
" Incrementalism " hasn't worked very well for the Democratic Party's current big tent approach. What will work is really the question the polls can't answer. Because the polls, run and managed by " insiders ", won't ask the outsiders the correct questions, fearing they'll get an answer they won't necessarily care to hear. So it goes....