Well that has more to do with THEIR (lack of) quality than being PL proven.
Rightttt…but not always?
We can’t just say “oh well every player that’s succeeded from a lesser prem club and stepped up and succeeded at a top prem club is because they were prem proven” and then say the ones that flop at the bigger clubs its down to not being talented (enough), as I said most the players signed by the top 6 who are successes come from abroad and had no prior Prem experience…look at City, Bernardo KDB, Rodri, Dias, Laporte, Ederson, Akanji, Gundo etc. Look at Arsenal, Gabriel Saliba Partey Odegaard Martinelli etc.