Well, some time ago a guy was complaining in here that his elo was unbelieavebly high in TG - he was 2193, IIRC. Also, he was waaay below that in 1v1, not to mention he considered himself as an “above average” player at best. I won’t call names coz i don’t remember then lol. He mentioned “the game threw me vs the best player of the world” as he reffered to an 2.2k opponent.
As for the difference in 1v1 and tg elo “because he is best in tg”, i don’t believe in - in these proportions, at least. You can beat TheViper and MBL when with a friend, but loses to an moderate AI in 1v1? (poetic license for the metaphor pls).
I believe in op, TG elo inflantion is real. Some kind of pattern always existed, keeping numbers close - even Voobly and HD elo ratings, provided you played enough, weren’t different that much.
Also, i suspect that the disparity on the speed you achieve higher elo can affect matchmaking - for low elo startes, at least - but this is based only in my guts.