The point of skill contribution being enforced after provisional tiers is that admins can look at teams and attempt to place them into the divisions they deserve with the players they have.
COGU has some high div players, but they finished 5th (out of 6 teams in their group) in Div 2 last season, so they're demoted to mid. On the contrary if another team is placed into mid, and then adds new players to their roster, they could theoretically no longer be a mid level team. Teams gaining new players and then essentially sandbagging is why the skill contribution and hijacking rule exist.
Also important to note that ETF2L seemed to try and make the higher divs more exclusive this season, ie. we've gone from 12 teams in Div 2 to 6. They also originally didn't have a Low division (division separating Mid and Open), so Mid was a total clusterfuck of ex-Div 2 teams and then teams just out of Open. ETF2L decided to push some Div 1 teams into Div 2, and some Div 2 teams into Mid, which is part of the reason COGU is in Mid. If there was still 12 spots for Div 2, COGU would likely be there.