During season 3,4 and 5 more and more people I knew started playing League. At this moment I know nobody IRL who plays league any more and it used to be 15+. Its just from my own experience but it can't be a coincidence. It is hard to believe the game is as popular as during pre-midseason 5. It can't be that everyone around me and myself have stopped playing League but the game is still growing. Lets face it the game has been on a decline since season 6. Last season I still used to play and ranked queue's time were already double from what I was used during season 3,4 and 5 and I was a diamond player so queue timers were already higher than usual. I know the new champion select has also increased queue timers when it got introduced. RIght now I also believe the terrible balancing and gameplay decisions have contributed to this state because nobody wants to play top any more, jungle got killed and support has always been the less favorite so everyone is going mid or adc.
But it can't be the only reason. Balance has been pretty bad since season 6 and I remember people started complaining about queue timers since season 7 and not just streamers but also regular gold and platinum players started complaining. That was new. Last season was really bad in terms of everything. Gameplaywise it was a mess, damage across the board was way too high and many reworks and class reworks and itemreworks blatantly failed last season and Riot acknowledged that but made it clear to wait until preseason to fix things to not interfere with proplay. In the end it was too little too late and many got burned out of the game at the end of season 8. To make matters worse nothing got fixed during preseason only more problems arose with the removal of runes. I really believe because of the playersdecline Riot has set wider parameters this season to prevent even longer queue timers. For me that is the most logical explanation.