I don’t think that is statistically possible. Platinum is approximately 25% of the player base. Everyone above Plat is a total of 14% of the player base.
So you’re claiming that 25-50% of the players in the games you play in plat (25% of 25% is 6.25%). So, nearly 50% of diamond, master, GM, Top 500 players are playing on alt accounts in your plat games?
I think there is a more logical explanation. I saw in a youtube video explaining that there are players who climb based primarily on mechanical skills, others who climb based primarily on knowledge and game sense, and of course those who use a combination of the two to get to the rank they’re at. What it sounds like is you’re encountering people who have very high mechanical skills, and therefore look like they belong higher, but have failed to rank up because they don’t study the meta of the game and do what it takes to get the team fights down in a way that would take them to diamond and above.
3-6 per match even have open profiles, much less evidence of that large of a single season range? My observations are that around 75% of people in my matches have private profiles. (I actually record all my comp matches, and actually inspect all 11 players profiles as part of the video after each match).
In my experience, the number of Troll Throwers in SR 500-800 is dramatically higher than even in 1000-1100 SR. I actually do not see a single open profile thrower in the majority of my games. I still suspect some people of being throwers, but can’t prove it with their private profiles.
In my SR, having strong mechanical skills is very frequently evidence that they do not belong in my tier, since I’m in the bottom tier.