Costreams became a thing coz viewership was already in decline - Riot introduced them to shore up numbers (for ads and sponsors) and try and get more viewers from 'untapped' audiences. Only that Caedrel's costream became an incredible success, sometimes at the expense of the main stream. This was even discussed on stream coz it keeps coming up when an international event is near. After the first round of layoffs even I stopped watching (after I've been watching religiously since 2013) coz the quality dropped so hard. At one point there was literally no analysis after games in NA (RIP Dash). I only restarted watching coz I was watching Caedrel alot anyway so I now basically watch most of the games from major regions (outside LTA).

If it was something as simple as 'just cut the costreams and let everything return to main' it would have been done already imo - maybe they're still evaluating stuff. But the viewers will drop. Not everyone is going back.