Exactly. You don't seem to be much of a student of history in general.
The GOP is basically maxxed out. They made huge gains throughout the Obama years, mainly due to Obamacare, which was perceived as an overreach by the electorate (even though Obama basically had a mandate for it in '08).
History tells us the following: it is rare that the party in power makes gains in a mid-term election. Beyond that, it is rare that Americans give one party the reigns of power for too long. Americans are mostly purple - they prefer split government.
And as much as the Dems bumbled this, I think Perez and Ellison are pretty capable leaders in general. Given Trump's historic unpopularity, they will be able to win a lot of races in '18.
Too bad for you guys that Georgia doesn't decide the whole House.