if HRT has so many benefits to our health I.e protects bones and heart disease then why is all menopausal women not on HRT.
The main reason is the total lack of education regarding menopause and HRT, largely the result of poor standards of primary care. Nearly every day on this forum someone reports back on an ignorant/unhelpful GP and that will be most women's main or even sole point of contact with healthcare.
If GPs don't help women confront menopausal symptoms and educate them on HRT and its short- and, crucially, long-term benefits (rather than either ignoring them or mindlessly prescribing anti-depressants just to cite one example) then patients won't be aware.
I often have this discussion with my mother who didn't take HRT and has the classic triple whammy of osteoporosis/cognitive impairment/heart disease, asking her why she didn't take it (and I distinctly remember when she was in her 50s that it was quite talked about, even in the mainstream press before the backlash as some high profile women like Thatcher and Miriam Stoppard and lots of 'power' women took it).
Her answer is always 'no one ever mentioned it' and to some extent that model of expecting the doctor to take the lead and be the "expert" is still prevalent though things are slowly changing.
At the same time, I often ask myself why so many people - men and women - don't do many other things that have been clearly shown to improve health both in terms of longevity and quality and life, eg/ not smoke or drink, do a few hours of exercise a week, eat lots of vegetables, nuts, seeds etc. So many killer diseases could be prevented and decreased with those measures and I find it inconceivable that one wouldn't do these things (and taking HRT is one of them) but evidently there must be other, less rational forces that guide people's behaviour and lifestyle.