The luggage problem has only got worse and worse over the past decade, and by the airlines’ own making. Carriers all started trying to make extra cash by charging for checked luggage, which incentivises people to take carry-on only, up to the maximum size and quantity of carry-on they are permitted.
If bags could be checked for free and people took only an under-seat carry-on for the things they need in flight it wouldn’t be a problem, but we know that’s never going to happen.
The amount of space is the amount of space. You can’t create more, because it’s literally constrained by the roof of the plane. It’s already maxed out.
The only thing they could do to make sure there was “enough space” is to have less tightly packrd seats and carry less people, which again they aren’t going to do for the obvious reason - profit.
Or - reduce the max carry on baggage dimensions, which I’m sure people would equally complain about. And would make them look worse against other airlines which “allow” bigger bags, despite there not being enough space to put them!