> Guarantor works a lot better for a young person starting out in a cheap-ass room in a shared place, whose parents expect this. For a flat and an older adult with retired parents on a low pension, or their own housing costs, not so much.

Absolutely. When my mother-in-law divorced and moved into a rented house, I was her guarantor.

I did have parents in 2003, but they lived 3000 miles away in a greek village where there was an ISDN line a 20 minute ride down the mountain, so not too practical. But this artcile is about 18-29 year olds moving in with their parents, not 50 year olds.