Democrats are pushing 'regristered voter' polls which are worthless since they include people who have never voted and those too stupid to follow what's happening. In Florida we have 'motor voter' - people can register to vote when they get their driver's license...those polls are worthless beyond how to highlight how many stupid people would vote if they weren't too stupid to find out where and how to vote.
poll internals are important in understanding these beasts. The registered vs probable voters is one key - just like you said many will not vote whereas probable voters more likely giving a closer result.
Also is the amount of ‘special sauce’ - often in the form of oversampling. I’ve noted some polls that oversample by double digits only to result in single digit harris leads.
I don’t hand wring about polls at this stage. Pollsters will sharpen their pencils so that they are not outrageously wrong. They lose business if they are too far off.