I agree overall. But come on 15k is like lem-supeeme with some smurfing 3k elo and even some pros. In 25k there are only pros/semi, 5 stack high level faceit and cheaters.
A soloq mm player is 100% individually better than 1, 2 or even 3 ranks above him. But he may not know anithing about teamplay, nades, basic strats, defaults, isolating a pick, spacing, ecc.
Thats why its unfair, at the end of the day cs is a team game and solo should lose everytime vs stacks, this becomes more true as you climb the ranks.