I'm a high silver/low gold player and when a friend stayed for a week at my place I let him play with my account (he is high plat/low diamond player) he got me in that week from 1800 I think it was to a bit above 3000 (solo)
when he left and I played again I fell fast to gold again (also solo)
now I manage to not drop to silver but it's deffintly different
so yeah I suck and I know where I belong and will probably never reach diamond on my own, low plat may be realistic but diamond is out of my sight
everyone who believes he isn't his right bracket should do the same and get carried to higher ranks and see if they can stay there on their own