I think it can vary still.
In some areas, you will find a big family detached house in a great area that hasn’t been touched since the 70s or before. The layout is lots of small downstairs rooms and tiny poky kitchen, but the potential is huge. The ‘undone’ price can be significantly below the ‘done’ price or sometimes not so much. There are less bargains to be had.
Part of it, as a PP said, is you can buy now and gradually do the work as you can afford it……if it’s liveable that is! It means you can buy the bid great house now and avoid future price rises, although you might not have the actual dream for another 10 years. BUT, the alternative might be a much smaller house or less desirable area and in another 10 years, the big house in the good area is totally out of reach.
If you want the done house within a year, the amounts you need to spend on a wreck are vast unless you’re in the trades. Especially if you do t have a very unique taste, it might. Well not be worth the aggravation of the project.
The thing is though, many people can’t afford the completed big family house in a good area. They can afford a smaller house in a not quite so good area. It then becomes a question of how much/long you are prepared to live in the iffy decor and layout for. Some people will do it for years. I’ve known people. On very modest salaries end up with amazing large houses in desirable areas, because they bought the wreck and did it gradually over more than 10 years. They and their kids lived in single rooms and without hot water etc for long periods. That was the ‘cost’ of getting what is now an amazing house.
Personally I don’t enjoy DIY and don’t have much vision for it. I’m also not terribly fussy and a decent, pleasant neural kitchen and bathroom are fine for me. I don’t. Have yearnings for very particular aspects. So I wouldn’t take on a big project. Consequently, I will probably never have the biggest house or house in best area I possibly could have. That’s fine by me, as I don’t particularly value those things anyway. But I know lots of people do and I think they deserve a reward for going through the hard slog.
Some of it depends on the market as ever too. If prices rise substantially, even though the cost of doing the work goes up, the price of done and undone houses rises and big houses rise by more. So buying a wreck can allow. You to get the house you won’t be able to afford in a few years. I think fortune favours the brave, even if not as much as it once did.