You may have a point with regard to individuals but that isn't the clubs and it is difficult to prove, even if there is any, direct involvement. I would think, for the reason I'll expand on below, that club involvement is highly unlikely.
In certain sports it's far easier to get away with using PEDs for the simple reason that the people involved are far fewer. Wrestling, weight lifting and even cycling comes to mind (despite the size of top pro teams). So generally that would be mostly individuals and their coaches. Pro cycling teams usually have 10-15 riders plus coaches, and would seem to be the exception to individual sports, where PEDs are prevalent.
Compare that to football. A squad of 22+ in the first team, then reserve teams and U21, management, coaches, medical team, owners and hangers-on. Even if the majority were not aware that's already an awful lot of people that need to keep a massive secret, indefinitely. And that's even before we consider disaffected leaving the club wanting payback, agents, ex-players, accidental slippage in public, drunken players, wives & partners, media involvement - where this would be a huge story that could make a journalist's career, and so on.
It's utterly impossible to believe that, if this is endemic to even just PL clubs (and if it was widespread then of course all major leagues in Europe, and maybe EFL leagues too, would be doing it), it could have been kept secret over all these years and by all those players etc. at all those clubs. You would have to be a serious conspiracy theorist to believe that was possible (though I know there are some whoppers of that ilk on this site) !
Non-banned substances is another subject entirely. If it's not banned it's legal until it's declared it isn't. Whether we like it or not.