This is an interesting thread, I've always wondered this too! I own a very small house outright (that was luck in my divorce), and have just retrained for what could be quite a good career (it really depends what I make of it) where I could earn around £50K+ pa. Not amazing but not bad either.
I live in a decent area and my house is now probably worth £165,000. It will sell relatively easily I think when the time comes. I want to move to another area of the country to a forever home the likes of which are around £700,000. I don't mind (in fact would love) a doer upper which would be cheaper than this, although I'm not sure where I want to go has many of them left! But, you only need one, I guess.
The steps to get there seem doable, if pushing it, yet a long road ahead! I'm already 50, divorced, with the prospect of possibly an inheritance of between £50,000 - £100,000 at some point, but certainly not guaranteed, and it could be 10-20 years away anyway.
I live quite frugally I think as my income's been very low whilst I've been retraining. Little savings since divorce.
So from what I've gathered on this thread, it comes down to a lot of luck, hard work, living frugally, having a decent income and possibly having an inheritance.
I'm wondering what my interim measures might be now. Some helpful stories on the thread, thanks!