The women who put on weight post-menopause tend to be those who were sedentary in their youth (perhaps they were lazy, perhaps naturally slender so no thought to health or exercise) and who have carried those poor habits into their forties and fifties. Sometimes injuries and arthritis make things worse, medications etc.
Well, I spent most of my youth walking miles - long dog walks, long walks to school, long walks around the city where I went to university. Then I started a job where I was on my feet all day, then walked 2 miles home to decompress. I was already overweight at this point, but it didn't sit on my middle.
Then I had kids in my mid-late 30s. They stole my arse and replaced it with tummy blubber. The minor joint niggles which had constantly plagued me all my life also began to bite. I had a ligament in my foot tear in my early 30s, not even doing anything strenuous. Turns out I'm hypermobile, but had no idea that it was a thing. I have days wen I can't reach my feet to put my socks on or my arse to wipe it. I'm struggling with trigger finger this week. Doesn't affect how far I can walk in itself, but the same hormonal soft ligament shite means that I have a stiff hip and keep twisting my ankles on uneven surfaces, even with supportive trainers.
With the problems i do have, eve though I'm mobile and feel better long term for pushing myself to my physical limits, I do accept that, if i see someone obese using a mobility scooter, it's fairly likely to be inactivity caused by physical difficulties leading to the incapacitation rather than them getting too fat to walk because they never ever exercised.
A few people in their 50s that I'e known needing joint replacements but unable to have them until they lose weight have been unable to keep their weight down because of the joint problems, plus medications that managing their pain directly or indirectly leading to weight gain (I take amitryptiline and naproxen, both of which have weight gain listed as complications)