Psytrance came out of early german trance from labels such as Sven Vaeth's Eye-Q.
Eye-Q 1991: https://www.youtube.com/watch?v=lApfaxi0QZw
Harthouse 1992: https://www.youtube.com/watch?v=d146LKl2ixU
This was Goa in 1991: https://www.youtube.com/watch?v=3fnBz6IOolk a very special period in time
https://www.youtube.com/watch?v=VT7lwdui4HY
The KLF became more theatrical and were the biggest singles selling act in the world in 1991, then retired in 92, ceremonially burnt a million pounds and deleted their entire back catalog.
This sort of techno-poetry track from Anne Clark in 1984, "Our Darkness" seems related to "What time is love". Although its surely not trance.
I'm a kid of the late '80s and '90s and that wouldn't have been shocking for mainstream listeners back then. I'm especially thinking of Eurodance music which was pretty massive and popular in the early part of the '90s and which sounds very similar in some respects to the music in your YT link.
It's also true that times were different back then, and for the better, just look at the MTV Top 10 of 1994 [1] and you can see bands like GreenDay, Sound Garden, Nirvana or Smashing Pumpkins. These type of bands wouldn't make the top 10 of popularity charts in this day and age (with the exception of GreenDay, probably). I mean, just look at this "Black Hole Sun" video [2] from Sound Garden which 13-year old me was watching during prime-time on MTV while doing my homework, this was seen as totally normal back then. Nowadays I'm afraid these type of music-videos and art-creation in general are out of prime-time media. The '90s were a lot more daring than today.
No it didn't, psytrance came from goa trance for which the foundations were laid in the 80's before trance popper was a thing. And what is liquid trance? Never heard of it.
But not to make this post just about whining, here's possibly the first trance track ever made, since we're talking about it. https://www.youtube.com/watch?v=MT9pH9C7Oew I'm not from the 90's so I can only imagine how shocking this music must have been 23 years ago.