It is always nice to see someone noticing the same things as I! As I have suggested in the same topic that @WoodsierCorn696 linked, I think that, because of this issue, both in matchmaking and in Elo point allocation, the average of the Elo should be taken on an exponential scale:
And it really is an issue: When I team up with someone who is way lower ranked than I am, the match is almost guaranteed to be too easy for my team.
As has already been pointed out, though, this is not the only issue plaguing team rankings. The most important problem is team Elo inflation, which @WoodsierCorn696 goes into detail in the topic he linked.