My theory on matchmaking.

I would not be so quick to blame streamers, the "skill" based matchmaking is designed to behave in a specific way:

Much as I don't care for most streamers/content creators, as they tend to have VERY distorted understandings of the game over the normal player experience, GM is very much correct on how SBMM works. It's based on your previous performance, and it is known for violent whiplash in game quality. But the unfortunate news is, this is not an accident, its intentional.

Addiction is the core driver behind this. Apex has come to the conclusion that it does not need to put you in fair games to keep you engaged, it just has to feed you that one "bot lobby" game where you overperform to make you feel good, then it can beat you over the head with sweat lobbies knowing you will keep playing for the hopes of that one good round again.

Preds/masters also need lobbies to play, but remember that diamond-pred is like what, barely even 10% of the population? None the less 10% of the population that even bothers with ranked. In order to keep them playing without several minute long wait times, they use this "feeding" based SBMM to keep the top 10% active, and compensate the "fodder" with the occasional bot lobby.

Worse yet, is the misguided understand of the kind of lobby you want. The game may think "lets get you some better teammates" but does not understand that many of those "better teammates" are just solo-sweats without an ounce of teamwork in their blood. Some people like myself are just fine playing games where I get all of 1 kill but I feel like I played with a team that actually worked together. I am just fine with a game where we play smart, get all of 1 kill at the very end of the last ring and win, but SBMM thinks we did poorly because we did little damage. Its clear that SBMM has no idea how to measure "teamwork" yet it is such an important stat to having a good experience. (worse yet are the content creators that want the game to be even more toxic to teamwork by disincentivizing support play like revives)

All of this is of course not healthy for the game, but you would be hard pressed to tell if the only metric you read is "player" count. The easiest give away is the hour that is Apex's peak player count on steam charts. It says that either apex has an extremely unbalanced regional following, or there is clearly something to these "players." Given the existence of actual bot lobbies and the extremely noticeable smurf/alt problem, its not a wild conclusion to think there is a massive bot problem.

Point to be made, the SBMM issues are not made "for" streamers, its made to use addiction to keep people playing for that high of a bot lobby match. There is clearly a reason why things like the 4k badge and 20 kill badge exist, its not because they want a properly balanced experience.