Here's what a uniform normal polling error would look like for either candidate according to Nate Silver's current polling averages.

So yeah, we could very well see a 7 battleground state sweep by either candidate.

Typically polling error is correlated, especially among similar states. So if polls miss in Wisconsin, it is very likely they miss in Michigan, and so forth.

So if anything it is probably more likely than not either candidate wins most of the 7, rather than photo finish.

And not all states will necessarily miss the same direction of course. In 2016 and 2020 we saw some states have perfect polling and a couple states actually underestimate the Democrat.