Incels are a natural phenomenon on the planet. An universal state whether you are a fox, a wolf or a human.
In most animal species, most of the males does not get to reproduce, more like the top males in the pack gets to reproduce and pass on his genes.
The existence of so many surplus males allows for genetic diversity.
Unlike in many animals, the more intelligent humans managed to reduce the problems (but is actually impossible to reduce entirely), by methods such as arranged marriages, rape and slavery and therefore incel problem is reduced at the expense of inferior genes being passed on.
As feminism taken off in the past, society is rolling back these anticompetition measures more and more everyday.
An example:
Status no longer mean much (as women can work on their own)
So what is there for women?
Competition is back to the cave men era.
Either you have to be above average in status to betabux (most men can't get there) or have good looks.
TLDR
Incel is evolutionary mechanism with surplus males.
Humans reduced inceldom problem
Society is now rolling back these anticompetition measures