Men do garner a lot of benefits from this social system but men are also extremely harmed by patriarchy, but they are too addicted to the slight little bit of power it gives them and made too insecure by it to take note - and like a lot of people in society, most men are sheep, simply following the crowd rather than thinking for themselves. The American Psychological Association recently issued new guidelines for working with men and boys based on 40 years of research that clearly indicates that "traditional masculinity" is extremely detrimental to boys and men - as well as everyone else. So, I agree with a lot of what you've said, but as a social scientist who specializes in this area, I do want to point out that it's overly simplistic and not true in the least that patriarchy is actually good for men in any but the most ancillary ways.
Boys brutalized and victimized by patriarchy more often than not become patriarchal, embodying the abusive patriarchal masculinity that they once clearly recognized as evil. Few men brutally abused as boys in the name of patriarchal maleness courageously resist the brainwashing and remain true to themselves. Most males conform to patriarchy in one way or another.
Hooks, Bell. The Will to Change: Men, Masculinity, and Love (p. 28). Atria Books. Kindle Edition.
I emphasized that patriarchal ideology brainwashes men to believe that their domination of women is beneficial when it is not: Often feminist activists affirm this logic when we should be constantly naming these acts as expressions of perverted power relations, general lack of control of one’s actions, emotional powerlessness, extreme irrationality, and in many cases, outright insanity. Passive male absorption of sexist ideology enables men to falsely interpret this disturbed behavior positively. As long as men are brainwashed to equate violent domination and abuse of women with privilege, they will have no understanding of the damage done to themselves or to others, and no motivation to change.
Patriarchy demands of men that they become and remain emotional cripples. Since it is a system that denies men full access to their freedom of will, it is difficult for any man of any class to rebel against patriarchy, to be disloyal to the patriarchal parent, be that parent female or male.
Hooks, Bell. The Will to Change: Men, Masculinity, and Love (p. 27). Atria Books. Kindle Edition.
Getting more men to recognize this might help them want to put more effort into creating healthier norms of masculinity and a social system less steeped in domination and control.