I think women sometimes give up mainly because of the progestin/progesterone side-effects of HRT.
Norethisterone because of its testosterone like action, and Utrogestan daily (when taking to shed the lining ) the amount you have to take is almost the equivalent to supporting a pregnancy. It can be taxing as your body gets older.
Sadly HRT is not an exact science, if you do have a hysterectomy and take only estrogen, this can lead to weight gain and estrogen overload even after menopause.
Hormones are very powerful, even are own can cause problems.
Its all a balancing act.