In The Force Awakens we saw some Senators on balconies or something as they were getting nuked.
That is the one and only piece of evidence that a post-Empire world existed. And now it doesn’t exist, because they were nuked in TFA.
Otherwise it’s exactly as if the Empire never lost power. Perhaps an orderly off-screen transition of power from Palpatine to Snoke occurred in this universe.
It was a complete soft reboot. Somehow they’ve convinced fans to insist that the First Order is just a small little imperial remnant despite all evidence to the contrary.