I have a theory and I wanted Turkish fans to confirm whether or not it's true.
I think many people forget that Oxygen was arguably one of the most successful Turkish teams of 2021 in terms of their consistency. They were always able to qualify for EMEA Challengers and consistently won a couple of series each time, although not enough to qualify for the international stage.
Essentially, I believe that the disbanding of Oxygen at the end of 2021 caused a collapse of the Turkish scene since the players of Oxygen were scattered across various Turkish teams leaving BBL as the only Turkish team that was competitive enough against European teams.