Yes it has.
Since 2015/16:
Spurs have gelled, in particular their defence and attack, and have added numbers to their midfield. They have improved under Poch every season and are quite good now.
Chelsea have been oscillating, but they showed a definite improvement after the Jose/Hiddink season. They added Kante, Hazard/Costa stopped sulking, and the switch to a 3-4-3 took them to a title. Now they've lost Matic and Kante and seem to have gone down a few levels.
We have added Lukaku, Zlatan, Pogba, Bailly, Matic and Mkhi and have gelled very well defensively under Jose.
City have added Ederson, Stones, Danilo, Walker, Mendy, Gundogan, Sane, Bernardo Silva, and Jesus, and have a very exciting attack under Pep.
Real have their star player, one of the historical top 10 players, 1.5 years older and in the middle of a decline, a series of injuries to Bale, Benzema has dropped off form for about a year now, they've lost Pepe, IMO their best natural defender, they've sold James Rodriguez and finally Morata.
Barca's star, probably the best player ever, has also aged a bit, their main striker has aged a lot more and has been mostly off form, and they've lost the most expensive player in history, a future BPITW (Neymar). Iniesta (and notice the theme!) has aged, Dani Alves left, and Busuqets no longer looks as good without their old playing style.
Bayern is almost uniformly about ageing - Ribery, Robben, and Lahm were three of their best players.
Juve have lost their midfield star and their central defender (Bonucci), the rest of that 3-man CB combination is declining rapidly too (Chiellini and Barzagli), and Buffon is about 40 now.