Has it though? Look at all the major events in the 80s 90s and 00s. The world is pretty normal. People might be more aware of things, but I am betting that feeling is due to 24/7 media and social media shoving high definition images and videos down everyone's throats trying to sell ads with click bait headlines.
Have to agree, look at any part of history and mankind stands out as cruel, misogynistic, hardcore unfair place. People just accepted all this, death and suffering as common part of life.
Reading up on what is called neurodivergence, I can’t help but wonder if many mental illnesses are just normal human reactions to a state of domestic and world affairs.
For example, if society moved in a way that rewarded behaviour that would have been considered pathological in the past, would those people who cared enough to actively resist the tendency be more likely to be deemed mentally ill?
I know psych was weaponized like this in communist countries, but I can imagine it happening more pervasively and organically in democracies, from the bottom up.
Back to your point, instead of eg anxiety being something disordered, maybe it’s a normal expression of human behaviour but in a world where the opposite traits are rewarded. Maybe 500 years ago or 100 years hence, the anxious are normal and confident optimism will be pathologized.
Mental illness has no stable meaning other than in relation to the society which it inhabits. The disorders are defined based whether they are serious enough to affect your ability to function in the target society.
I think it does depend but there is something approximating an absolute distinction. For example low functioning autism or severe schizophrenia would be debilitating in all but the most advanced societies.
However, high functioning autism or mild schizotypal/schizoid disorders probably would not be debilitating unless the society had a low tolerance for eccentricity.