In my mind and my experiences of the past (find it funny seeing me as a veteran nowadays)
Offering Full Service / Service Complet : This to feel very transactional as a listing and i expect once im there only thing i can expect is a CBJ and sex, in a very transactional way. I saw a movie when i was a kid (don't remember the title) but the guy was with an escort and they arrive in the room, she undress and she says "en piste" (lets get started) and its super like "i have a job to do, lets go"
All Safe Services : Something close to a GFE in term of experience/atmosphere, but no kissing, cbj only...
Safe GFE : Usually this mean CBJ and either no DATY or covered DATY (its a thing apparently), but kissing is still allow
GFE : BBBJ, DATY, Kissing / An experience close to what would it be if you were with a girlfriend or a one night stand. Its not transactional, there is some "warm" (ambiance chaleureuse) etc
GFE+ : All the above of GFE but cim possible either included or as an extra
GFE++ : Swallow is added
PSE : This one is trickier. It usually mean more wild sex, closer to what you would see in a porno, but it can also mean in term of sexual acts either COF or Greek. Usually tough they say "PSE Greek" when its Anal.
Now thats just my interpretation and what i THINK PERSONALLY should be the language used.
As for the point of the OP, i feel its tricky on this too. I think the peek was probably 2011-2013 (but keep in mind i started in 2009 so maybe i was still too green in my "rookie year" to tap full potential). So much agencies with pretty big rosters, still great prices, many GFE+ all included depending on agencies. Then things evolved but at the same time, can't say the market is "bad" these days either. There is still a decent share of big agencies with numerous talents, and some are truly superstars that would have nothing to envy to the 2011-2013 rosters. At 260-280 i think it is still fair price considering monstruous inflation in life. I think agencies show more consistencies these days too when it comes to cancellations (or lack of), appointement time and providers attitude.
Where i think the market took a bit of a dive, and i am really sorry to say it, i don't want to offend anyone, its in the indy market. Its not everyone of course, still plenty of great indy providers, but its not rare to see providers in the 600-700 range for base GFE, booking is often harder for clients too (screenings, deposits, providing a lot of infos). Online/technology has made this business great during the 2010s but it then made it harsher when the technology truly developed. If you would go back in time and tell 2012 me to have a booking i would need to send money by email, send a picture of me or even my infos like gov issue ID, i would had laugh at you. All you had to do was bring good ol cash and pay.
So is it better or is it worst? I dunno. Im not the best to judge as i book too rarely vs the high rollers of this forum. There is both improvements and downgrades to me.