We went right through the house a couple of years ago. Every room decorated, new carpets or hard floors in every room, blinds and curtains replaced where the old ones didn't match, light fittings replaced, bookcases built, a new kitchen and bathroom and a bedroom covered into a study. I'm very happy with it, but I will never do it again 😂.
Everything had to be declutterred, which is a task in itself, the organisation was daunting (particularly doing all the bedrooms at once, which was my daft decision), and it felt as though the house wasn't our own, as there were workmen and decorators in, which I find stressful. We slept on the floor for a week waiting for new carpets and beds to be delivered and the rooms decorated, the kitchen ran into snags and all the contents were in the dining room for ages - I'm hyperventilating just remembering it😂. I was about 63 and my husband is around to help. At 73, 83 or older it would just be too much, particularly if I was on my own.
In my area, bungalows tend to be on modern estates on the outskirts of town (the centre is old and built before bungalows were popular), so when one does come up for sale in the centre, where the facilities are located, they command a high price and are snapped up. I can well imagine someone selling a house that might need a bit of work and getting less than the cost of the bungalow, so if they are on a fixed income they might not be able to justify spending thousands on updating - the important thing is living somewhere with no stairs near the doctors and shops.