a) Prices for accomodation have gone up a lot in the last few years. At my university in the south west, rental prices for off-campus accomodation have roughly doubled since I was studying a decade ago (and at the time they were one of the most expensive in the UK). Even with the maximum maintenance loan it would only just cover the cost of accomodation (assuming you only need to pay for term time).

2) The means-tested grants and loans expect higher earning parents to support their children at university, but a lot don't. I believe in this case your parents can make a written declaration that they won't support you, which allows you to get the full loan and grant, but this option isn't made clear.

3) A lot of people are just bad at managing finances, and spend money on things they don't really need. Schools really need some sort of financial education, but I guess it's too profitable to bankers for people to be educated on how to be sensible with their finances.

(also I think the whole subject is way off topic for HN, there isn't even a FOSTA angle)