You can also blame the organizations and the tournament bodies themselves with such a decline in the esports scene. Most of them have resorted to greed, and only a small portion of the profits from these events actually go into the pockets of players. Even I as a player would surely be demotivated if this is what's happening in the scene wherein I spent hundreds if not thousands of hours just to be good at.
For sure to the largest extent I would blame the organizations because they have too large of a piece of the pie of the blame in this matter. For example making players too stressed and no longer interested in the game is a big issue because esport clubs don't have an agelong history and naturally people are going to fixate on the players not the club. If players are quitting all the time, as the big wave of resignations of pros that came around 2018, then yeah ofc viewership will keep dropping after a certain point. You can only keep attracting so many new viewers. But there are limits. So the clubs have large part of this responsibility. These clubs don't focus on enriching their players. They are focused solely on winning the big games and taking the huge cuts off adverts and sponsorships tournaments are getting. If they see that one of their players is underperforming, they wouldn't hesitate to drop them off and pick a new player that performs relatively well during the season. This is why in Dota, we have a post-TI shuffle yearly, which means that orgs are always quick into changing rosters rather than attack the problem at the fundamental level.
Many pros quit after a few years on organizations that they carried the flags of. One huge part is due to the management. The rest is because they want to join a stronger team to win. If orgs would just invest more on their players to bring out their maximum potential, they'd be a lot better team-wise and may even win tournaments with a roster they tried so hard to work.
