Nothing came along. You talk like subgenres were invented in one night and change our scene.
It's called evolution.
What you call as psychedelic trance evolved into 3-4 primary subgenres over the years. And those subgenres evolved into new ones and so on. Something that happens since the 'discovery' of music.
After all psytrance itself wasn't born in a day. It came from the evolution of goa.
If we detract full on, prog, darkpsy, suomi, twilight, techtrance etc we left with 5% (even less) of the psytrance artists. Artists who are not necessary psytrance (psytrance as you mean it), but their sound doesn't have a name yet. Which means if I give a name to their music like psynight or dawn trance then they are immediately stop being psytrance.
Well just because most of full on is bad that doesn't mean I can excluded from the scene, does it?