I’ll try to break it this down, the best I can. If you have no interest in my thread, feel free not to respond, your announcement of disinterest is not needed.
Tl;dr : series of variables create a window of “suck” aka, losers queue. It doesn’t have to track your previous win rate to establish the losers queue. But ultimately - shills and paid actors try to draw this into a rank discussion, but it’s not about rank, but match quality.
Yes the game does NOT “track” historic win lost rates. You just get TWO values. One is the solid Mmr value, the other is an uncertainty value. Both of these are used in matchmaker / team balancer to make a lobby.
Fundamental truth, the less uncertainty, the more likely you are paired with people with high uncertainty (so you can drive their uncertainty down).
Another fundamental truth, your sr follows your mmr, and it’s your sr that determines your team balancing (in addition with uncertainty). Sr MAYBE determines the modifier you get after a match, could be Mmr too.
When you go on a win streak, your Mmr let’s say starts at 0, and your uncertainty is at 0. Let’s track what happens. And this is past placements, and calibration.
First 5 games, your Mmr goes up because you certainly have beat people below, at and above your current Mmr. How much does it go up? WHO KNOWS?? Depends on how high you beat a person it paired you with. Since Mmr is hidden (OBFUSCATION), you’ll never know just how high your Mmr went.
Best case it went up to the “next level”, your sr however is still mapped to your “previous Mmr”, remember it follows and maybe never exact.
Your uncertainty… has now gone up too. You got some games under your belt, the system thinks your closer to your current Mmr.
Okay, you luckily win 5 more games. 10 games in a row, I have done it, maybe even provided codes the forum in the past, so not impossible.
Mmr, goes “up”. By how much? WHO KNOWS??? (OBFUSCATION). Your sr however might still be mapped to your original Mmr, maybe “next level” but certainly not where your current Mmr is.
Your uncertainty, oh boy it’s starting to get very high certainty (this too is unknown, but some modifiers do indicate low certainty - “calibration”, but we’re past that).
So your Mmr could be 2-4 levels high (who knows), your uncertainty is more “certain”. Your sr is still “far” compared to your Mmr. But your sr still modifies your sr bonus? (This is why I think it’s Mmr, because to help get your “sr” to map to your Mmr FASTER, why would it use a lagging value? You could be playing at diamond but your sr still in plat, to help you see the diamond pixel icons I figure they want to boost the sr to reflect your Mmr - but… WHO KNOWS???)
This is when things get … sad. 
you’re now playing at a higher Mmr. And yes, the overall system works, your playing with and against people who are probably better (not by much) than folks 10 games. HOWEVER, your certainty is higher than it was 10 games ago. So you’re playing with better players with less certain teammates (and maybe opponents however if your opponents have lower certainty - WHO KNOWS).
You lose a game. Happens to everyone. Even smurfs. But maybe your Mmr doesn’t drop as fast cause of your certainty is higher? How many games does it take to get you back to an even play field? - WHO KNOWS? Maybe it has to be the same number? Maybe it has to be more because your certainty is higher? BUT for sure, now that your certainty is higher, you’re attracting MORE uncertain players. So now your slightly stuck at a higher elo, but your getting more and more players who DONT PLAY as much as you did for that season (I’m accelerating a little, typing more than I wanted).
What happens to me… win streak… 50/50 for awhile, but because I play more than casually, I attract casuals. I attract casual stacks… it gets to a point where I can’t “carry” and I spiral into a loss streak until my certainty has to take a hit or I switch to a different account.
So yes, the system doesn’t track loss streaks. But what clings to you is certainty, and that rarely goes down. So the same range of sr you breezed up, now is harder because your attracting “different” teammates. Yes, it evens out to produce the 50/50.
You’re going to get to a place where you can carry those casuals and your opponents are not as good. But at what cost? Match quality. Which is why this always been about match quality and not rank. At the end of the day, no1 cares about their rank (sort of), but when loading in we want people of like minds playing together. We can’t get that cause of certainty matches with uncertain.
How to fix it:
Add “timescale”. As the season goes on, your timescale to your Mmr shields you from those who just started comp. The more you play, the bigger and denser your shield. For queue times and the grains of sands the shield breaks down, but ultimately you’re more likely to play with people who have been playing just as long as you have.