Michigan and Pennsylvania can be won back somewhat easier, but it won't be with the exact same coalition that Obama or any previous Democrat was able to put together.
But see, that's the whole issue. Becoming the party of urban centers and suburbs is
not a viable strategy for the Democrats. Even if they can somehow muster an electoral majority with these coalitions, they will still be permanently locked out of the House (
even with fair redistricting) and probably the Senate too. It will also lead to a voter base that's unwilling to support any serious redistributive policy, thus turning the Democratic party into the party of affluent, "cosmopolitan" managerial centrists who don't give a crap about poverty and inequality. That party would not even be worth supporting.