The average salary in the UK is £26,500; monthly take home from this is £1,759.
On £26,500 I can borrow about £93k, according to mortgage affordability and assuming I spend £400 pcm on the train to commute, don't have any tube to pay and spend £150 pcm on food, toiletries and all bills.
If I've managed to save £9k, somehow, and the market hasn't gone up in the time it's taken me to save that, then there are a couple of one bedroom places in, say, Gravesend, that I can buy.
But of course, many people work hard, save as hard as they can, and earn well below the average salary, especially if they are less than ten years into their working lives, probably the time that most people want to own before they start a family.
Yes, there might be two salaries etc but do you see how the credit squeeze has changed the balance?