Why decay/seasonal-ladder-resets is neccesary(and why I hope they are implemented soon): Lets say an average player starts playing. He struggles for his first 50 games but constantly improves. After 100 games he is way better than at the start but he has to win a LOT of games to make up for the losses he took initially in the learning process(if he wants to get a good w/l ratio and ladder position)..
not at all, ladder position is solely based on ELO, w/l ratio has nothing to do with it.
When you play with people stronger than you and win, you get a lot of points, but if you lose you don't lose much.
Other way round when you play lower ranked players, you win just a few points but risk of losing a ton of them.
That's why you can't climb to the top if you're matched with people with lower skill all the time, you might win 10 games in a row but then in just a loss you lose all that they gave you.