Nah mate, you pulled that one out of nowhere. It's pretty widely understood our mental health issues are due to lonliness and social isolation and social media (fake virtual socialising) mate.
There is a distinction to be made between loneliness and solitude though.
One can feel hopelessly lonely in a crowd, one can also find great solace in solitude.
In fact, another great cause of mental health issues is the apparently growing inability for people to stay still, instead constantly vying for interaction (and often resorting to that quick virtual dopamine hit loop, sometimes even when face to face)
There's balance to be had, both ways, but not everyone have the same needs.
I'm very aware you can be lonely in a crowd and find solace in solitude. I've done both. I'm talking about my real-life experience here not a hypothetical. Working 100% remotely as a young person trying to find your place in the world is crushingly lonely. Choosing sometimes to spend my weekend just doing my solo hobbies while other people are going out, without giving into fomo, is solace in solitude.
I agree, not everyone has the same needs. But I think on average the majority of people would benefit from or would be able to handle a mandatory hybrid situation. If a few fully remote jobs remained that may satisfy the few unusual people who are actually that disturbed by social interaction, or live in such odd locations that it's not possible for them, that would be great. And I am absolutely sure those opportunities will remain. But I think it is bad for humans to aim for a mainly remote working world, both for our mental health and for the dynamism of our collaborative work. I really believe that people who genuinely thrive significantly better in 100% remote vs a couple days in the office are less than 10% of the population. We are social animals and we increase our risk of dementia the less we socialise, it's just our biology.