You deliberately ignore the different financial realities - PSG isn't going out in the group stage like Zenit because their money allowed them to build teams too strong to go out in the group stages. They still don't always make it straightforward either - look at this season, look at whenever they got drawn with City, look at 18/19 when they needed a Di Maria last gasp wondergoal to qualify...
The lack of domestic challenge means they're often unprepared for the dog fights of CL, when they face teams of similar level and end up getting dragged into battles of survival, which they almost never win. PSG's eliminations rarely came as a result of a better team just outplaying them - it's either spectacular collapses or self-inflicted defeats. Going back to 12/13, only 4 times were their eliminations either not spectacular meltdowns or self-inflicted. 4 out of 12. Hell even in the league, the few times they got an actual rival capable of challenging them, they fecking lost the title. They have the biggest financial advantage over their competition of any team in the top 5 leagues, yet they've been less dominant than Juventus or Bayern. Hell, since 16/17 they won the same number of league titles as Manchester City - the latter competing in the richest, strongest league in the world
I'm not deliberately ignoring anything, could easily be i'm wrong, but not being disingenious. Why would i do that? I'm no fan of PSG.
Some of that i think only bolsters my point that the league strength is not one of the major issues. A significant part of why Zenit (essentially a de facto state funded club) didn't do better is because the league's international appeal and the quality of that generation of domestic players was not strong enough...plus Uefa at least half-arsedly enforced FFP against them at times. All factors related to the domestic situation and issues that don't affect Ligue 1 to nearly the same level; it does produce a great depth of homegrown talent that consistently transition to the big four leagues in large numbers, and is a big enough draw ( when welded to the money psg are throwing around) to pull in genuinely elite players
Is having only occasional rivals and a huge financial advantage not a problem at all? Of course not. It is a drawback, and there are definitely various knockout games that arguably show they weren't used to "dog fights" (which in all honesty i don't think came up all that often for Juve or Bayern domestically either during their long dominant runs) and/or didn't possess a big game/club mentality as a collective, though that last aspect can be attributed to big teams in the top four leagues over this period too; swimming in deeper waters doesn't automatically toughen a team of great financial potential up quickly. just look at United or City's many exits (which we could pick apart too) before they got it right. However, these issues, and the fact they tended to struggle when a good domestic rival did emerge, comes back to my point in the first paragraph...i just don't think they've ever been THAT good to the point where going out in the CL knockouts against equal/better teams should be seen as some huge failure, or reason for condemning the entire league. This is purely looking at things from the on-field reality in relation to the strongest top four league clubs of the era, and not to argue against the idea Qatar/PSG leadership couldn't have used their riches in a wiser fashion to build smarter, better balanced squads.
It comes back to those very fine margins of late knockout rounds. When you've made a final and a few semi-finals, not much has to go the other way on the day, even if a team is outplayed overall, and you have been talking two/three time finalists, or even winners. That's not the mark of a team being truly substantially held back by their league. I find it highly debatable that if we were to take those Qatari-era squads and have them play out all those seasons in one of the big four leagues that it would necessarily improve , or toughen them up, beyond what they've actually produced as French league champions. The crucible of the premier league certainly hasn't forged a financial powerhouse like United back into greatness purely on the back of its greater competitiveness alone, and it took City a long time to get things right, during which PSG have been in those late stages three times out of the last five tournaments.
