How are you supposed to improve?

When riot every year will send you right back to where you was 3 seasons ago. Same shit happened to me last season that it did on this season. I was silver 3 took me all season to climb out of bronze and to silver 3. Because if you know bronze - its like a black hole and will keep you stuck in it because of trolls. I finally made it to silver 3 with 3 lp no big deal you know but I was actually having good games at that level for my skill set. Then I went to my revisions. I went 7/10 I was excited that I did so well and I was like yes atleast I wont drop to much. Comes to find out I got demoted to Bronze 2. Like seriously? The same exact thing happened last season. Seriously how am I supposed to keep improving if I keep getting reset back down to bronze and have to grind my way back to where I should be to begin with. This system is a joke. Its like the government - its keeps the top 1% at the top and shits on the rest.