That's a perfectly reasonable question, and the answers are many. It was the house she and dad bought together, and after he suddenly and unexpectedly died, she was really attached to anything which held her memories of him. They had been active in volunteering in the area and had many friends and a strong connection to it, and she just didn't want to move anywhere more affordable where she didn't know anybody and had to "start again". She had an extensive garden which was her main hobby and which gave her an enormous amount of pleasure, and she was loathe to give it up (it was admired by local people and when she died, people came to take photos of it). Mum had Parkinson's disease at the end, and found mobility a challenge, so the house was easy to modify for her increasing disability. The truth also was that the house itself was kinda crappy and wasn't actually worth very much and she wouldn't have gotten much more than it cost for a unit in the area at the time (prices for units in that area were starting to get a bit crazy). After dad died she got all morbid and was talking as though she was going to die soon too, even though she outlived him by about 20 years lol. I guess she thought, why go to the trouble of moving when I'm just going to die anyway? I hope my answer hasn't bored you with rambling on, my apologies if it has.

Aside from anything else, I've seen a couple of examples of downsizing up close and in neither case did it end up with them making very much money on the deal. They just ended up with smaller places.

In the first case they ended up with a small apartment which they actually ended up having to sell some of their retirement investments to be able to afford after selling a large family home in the outer suburbs and paying all the costs associated with selling.

In the other case she moved from a large family home in the outer suburbs into one of those "retirement communities". The whole thing's a massive scam. You "buy" the unit but you don't actually own it, you only own a leasehold on it - something they didn't make clear to her at all. You're not allowed to even improve or renovate it. They impose rules on you much like a rental. And when you move out you're not allowed to sell it - they contractually reserve the right to sell it themselves and pay you a massively discounted amount for it. Essentially they steal half the value of what you originally paid in a time when house prices are going up as well. It's straight up exploitation of people who are old and struggling to even do everyday tasks, let alone understand complex contracts.