In the 1970s, it was usual for working class newlyweds would have to live with their parents until they were able to find housing. That's why second-rate comedians of the time like Les Dawson had so many mother-in-law jokes: there was an awful lot of resentment between young men and their mothers-in-law to exploit. There's nothing new about multiple families crowding into houses designed for just one family in this country - that's why there are so many pubs.
The Town and Country Planning Act 1947 has been identified as a cause of insufficient housebuilding activity, and new legislation is currently working its way through the House of Lords to alleviate this.
In the UK specifically the radical reform (read destruction) of council housing by the Thatcher government had a large impact on the housing market in the 1980s.
In 1970 you could basically buy any non-city plot of land and build a shack on it without anyone bothering you. Think of the back to the land hippies in California just chopping down trees and starting their little communes -- they'd be utterly fucked if they did that now, some Karen would rat them out instantly to planning and zoning committee.
In the late 60s/70s DIY builders were almost completely displaced by developers who lobbied for regulations that stomped out "a guy and his pickup truck" by and large almost anywhere with desirable land. Then the owners of those houses reinforced same to prop up their property values.
I live in one of the last remaining counties that didn't do that, and last year I built a house for $60k. Pretty easy if you're in a place with essentially no codes or zoning. My (fairly) newlywed and I built the house with basically no experience either.
And in turn none of the discussion you've replied to is relevant by your standard, because the OG article discusses the United States.
Funny someone else is allowed to discuss UK in regards to an American article, but I'm not allowed to discuss America on a UK thread about an American article.
The discussion was prompted by an article on sharehouses being banned in US cities, which prompted comparison to HMOs in the UK. One of those comparisons suggested that HMOs are a recent phenomenon and are a cause in the shortage of family homes in the UK. I replied to this by arguing that a shortage of family homes was also present in the 1970s, and that overcrowded housing for working families has been common throughout British history. You've replied to this with your personal experiences about building a home in the 1970s and dealing with building regulations.
The discussion about the effects of UK HMOs on wider housing availability is indeed a peripheral discussion of limited interest to most. Your comment, while of interest to me, was only tangentially related to my comment. I'm not arguing that you shouldn't have written it - as I said, I found it interesting - I'm just pointing out that it doesn't flow well from what came before it.
The Town and Country Planning Act 1947 has been identified as a cause of insufficient housebuilding activity, and new legislation is currently working its way through the House of Lords to alleviate this.