rank points are very few. Get a player I can't max rank for weeks

rank points are very few. I get a player and I can't play with him at max rank for days or weeks, by the time I have the full rank of 2000 rank points, I lose interest in the game. Why can't I get 10 rank points after every match? If you get a player, can you rank him up? Do you have to buy everything for money? If I open the 1500 diamonds it gives me 75 rank points, should I open 30 of them? This is not normal...