The only fact is what you said is a myth.
You don't dictate who is world class coach and who isn't based on personal opinion, to dismiss the likes of Rijkaard (he was great with NT too btw), Lucho (treble winning coach) and Beckenbauer (world cup winner,UEFA Cup winner) to suit your argument is laughable at best. Especially when you list the likes of Pochetino, Conte as world class coach while having an inferior career than them and it isn't even arguable.
Here is a fun fact: Last 10 years CL winners:
Flick: played for Bayern for 5 years, big team player
Klopp: Mediocre player at best
Zidane (3 times): Legend
Lucho: Worldclass player at his time, played for Barca and RM
Ancelotti: Was a player for big clubs
Heynckes: An international player who played for big club (at that era) with 4 league title and one Europ league title
Roberto Di Matteo: Also played in big clubs and was international with Italy NT
Pep:Club Symbol
Only one of 10 last CL title winners was a no body as a player (Klopp)
With leagues it will depends on which leagues, Bayern had coaches with good careers as players, Juve was the opposite during their time after Conte, Liga were mostly dominated by coaches with greater careers in past 5 year, EPL was more balanced.
And here is a more fact: there few dozens of players who reached super star level, few hundreds played for top clubs and few millions who played football just is. There are far more percentage of superstars making it as top coaches than any other categories, and far more players in big clubs than the no bodies too.
And again, the whole " Pep" effect shows lack of history understanding, Pep hiring wasn't a new experience at all, even his mentor Cruyff was hired by one of Europe finest at that time with no prior experience except coaching youth teams. Klinsmann & Van Basten were both hired for NT coach (before such job became retirement homes) with no prior experience, few years before Pep.
And then you claim that over a decade later, Pep is the reason Pirlo is hired? give me a break here. The world doesn't revolve around Barca and its success.
PS: Ten Haag is 50 years old coach, he is older than Pep, he isn't a young coach waiting to dominate the world
. He is doing things Koeman done a decade and half ago too. Nothing exceptional really.
Same with Tuchel, who could very well be in his last top club job unless Bayern Bayern be interested in him, otherwise he will most likely end up in midtable EPL team. He is 47, that is an average age for coaches. At this age coaches aren't young beyond 45, probably considered older at age of 55 or so