I will chime in an give a Silver I perspective here. I hope we can keep this constructive and not the normal of "well you just suck" kind of trolling lol. Yes I am a bit salty writing this as we got beat by smurfs 2/3 games we played tonight.
Background: I have played the game for 126 Hours as of right now. I am still daily learning about nade spots, sprays, when to buy, and other helpful hints from everywhere. I play with two other Silver I's as well. I understand you can learn something from other better players (such as angles, pop flashes, and such) I also understand I am not going to jump and start pounding out ranks within a few games.
Second: That being said, this is why I think smurfing is a huge problem though. ALMOST every game though we encounter 1-2 smurfs are on the other team with each dropping 25+ kills a piece. For a new player like me this does feel like a never ending cycle of hell even when we are all try harding.
I am getting to the point now where it's like I have no motivation to play MM anymore. We have also been aim botted only once so the cheater argument I just haven't seen much of it but 1 game.
I am fine with streamers playing on smurf accounts or someone playing on an alt account to play with new friends and show them the game. KEY: These people are usually not "try harding" and kinda just messing around, but those individuals are minimal from my experience in the 126 hours I have played. Most want to go in and destroy the lower ranks and usually what I have noticed is they are ranking up their other friends on silver accounts. I know it's not going to be easy playing at higher ranks, but I feel most new comers to the game are quickly getting discouraged of even continuing playing MM just due to a lot of the time not even having a chance at winning a game after 6 rounds. Some will argue well go play casual. Casual IMO is no where close to the experience you will get from Comp.
All in all: I think Valve will never do anything about people making alt accounts and smurfing and the main reason is simple... $$$$$. Valve isn't going to stop people from spending the $29.99 or whatever the price is now for another CSGO purchase. Some say I am salty..which first hand I admitted...but at some point having a competitive game with all similar true ranks would be nice. I think a change to the MM and Ranking system needs to be overhauled big time.