The size of the human animal has not varied much.

People really haven't changed.

What changed a lot is occupancy. It used to be that homes were multi-generational and families were larger. I don’t know in this context, but in Europe until recently, it was common for grandparents-parents-kids to live all together, with sibling of the parents often included and potentially their families too. An apartment occupancy rate around 5-7 was common, while single family homes where unheard of until last century. This strengthened social ties, smoothly provided care for who needed it, and made the family more economically resilient.

More space isn't necessarily a better thing, there are very real diminishing returns after a certain point. Plus, living space is both an asset and a liability - you have to pay to keep the space warm or cool depending on your local climate, and you also have to clean the space.

But note that the typical home has more space per person now.

70m² is a lot more for the modern family structure of two adults, 1-4 kids, and maybe a pet than it is for the traditional family of the old days where there'd be the man of the house, his wife or possibly multiple wifes, their kids (note that they would have way more kids than nowadays because of the lack of contraception and very high infant mortality that led to having to make a lot of kids since only about half of them would make it to adulthood), maybe kids from previous marriages, miscellanous relatives and possibly their families, servants (for example, IIRC in ancient Athens the average family had 4 slaves or so), and domestic animals, as it was common for urban dwellers to still have some animals like a few chickens and a goat or something, and pets of course.