Everyone who has ever bought a house or flat has an expectation that it will be large enough for their needs - whether that is a single person, a couple or a family with two kids. This is not a new development.

2 adults and 2 children on 16m2 with 2 working salaries. It’s not about changing standards, it’s about families with children needing enough room to have beds for everyone and hopefully still fitting a small sofa. Back in the day, that same family would be able to have twice as big a home with one one working parent, but that was before the whole market started playing chicken to see who could put themselves most in debt to carve out a little place to live.

I somewhat envy that time before the 70s where a family could live on one salary and have a house and car.

Today you can’t even buy a house with 2 salaries. If you are living on one salary you will be struggling and will not be credit worthy. The banks assumes a life-standard to uphold which not everyone can cope with. Even if you can live with less the bank follow it's idea of life-standard.

If you omit the second part of the phrase obviously the meaning changes. The commenter clearly said "large enough for a family".

I think it's a response to house builders building new property with really low floor area - many people don't consider that are sufficient anymore. It's a huge problem in the UK where property is advertised by number of bedrooms and floor area is hard to find - so we get houses with lots of bedrooms, but the bedrooms are tiny, and so the whole downstairs area is also small. Standards aren't changing, houses are.