The men who are successful with dating are already dating or active in places where they are finding better success than clubs and arranged dating events.
The men who are unsuccessful at dating are confused and wary about women, who are no longer the compliant trad-wife wannabes that these men were lead to expect exist in numbers by the likes of “manospherian” influencers like Peterson, Tate, et al.
The root of MAGA is the same as the root of “America First” (the early 20th century version): supposed humiliation/cuckholding/replacement of the white man.
For the first America First, it was rooted in the lingering animosities of the Civil War by “Southern Bourbons”. For MAGA (which is also a stolen slogan, btw), it was in the demographic decline of white births in the 1970s to below population replacement rates.
Not sure where you get the idea that “most men” are not dating. The description you make of what “most men” are doing sounds pretty much verbatim lifted out of something in the incel community.