Sure, OK. I guess if you find low ranks boring but aren't good enough to rank up then yeah, you're stuck. In that sense I agree with you in that I can understand why you are frustrated, it sounds like you might need to choose a different game that you are naturally better at.
I'm not convinced that this is entirely Overwatch's fault though. Any team-based game is going to suffer from lack of teamwork at the lowest of low ranks (which is what Bronze is). You can quibble about whether medals and plays of the game are to an extent negative reinforcement, but three of the medals are "objective kills," "objective time," and "healing done," many of the cards are for things like damage blocked, and those 'awards' aren't the basis of SR anyway. Being 'on fire' is the closest we have to a window into internal SR bonuses - and getting on the objective gives you fire points, and if you're on fire most of the game you get a card, and if you gain a lot of fire in a short amount of time you're more likely to get POTG... - but it's still pretty far off from what we know about how the SR system works.
The SR system rewards winning primarily, but also rewards you based on a variety of (sometimes hidden) metrics that say, "given his rank and hero, did he do more winner-like things than loser-like things this match?" Note that it doesn't decide based on how the developers think the game should be played, it judges you statistically by comparing your actions to those of winners and losers in other games. (By far the easiest way to game this system is to die less often. When you're dead you can't 'score' on any of these metrics, whereas when you're alive & doing stuff you're probably 'scoring' on at least some of them. But anyway...)
The defence of the design choice is that it would take ages for very good players to rank up (and for very bad players who were misplaced to rank down) if you didn't 'accelerate' the process by assessing the person's skill. I don't think this is necessarily optimal - perhaps it should be straight win/loss with the only modifier as your team SR compared to their team SR, or something - but I don't think it's what's holding you back either. I dunno, I haven't seen your games so maybe it really is gimping you. Sorry if that's the case. It's hard to know without looking over your shoulder as you play.
But like I said, I don't really understand your mindset because I genuinely enjoy playing the heroes I play even when I'm losing and my teammates are bad. I play Lucio, Mei, and Winston because they constantly interact with the enemy in funny ways (both in terms of their gameplay mechanics, but also their voicelines and stuff) and I find it very amusing and fun.
That's primarily what I get out of Overwatch. If I get matches with good teamplay then that adds another element I enjoy a lot, but I have fun pissing around too, which I guess is why I really like the game as a whole even though I'm ranked low and you don't. It's not like I get frustrated if I have a few 'bad' matches because I'm almost always playing one of the three heroes I really like. (That's not a judgement of you, just my hypothesis as to where we differ.)