OP I get it and it’s hard to watch but you aren’t helping things with that reaction.
You can’t hate on all the other teens, they’ve formed friendships and groups. Living with people can be very difficult and there might be a whole range of factors they’ve not chosen to live with your DD. (From personality down to her not washing up - just an example).
People feel the pressure and so they panic and sign up at once. The reality is in those early weeks many will have signed up to houses with people they will later fall out with or find closer bonds elsewhere.
The best thing your DD can do is just relax now. It will be easy to find a spot for one person (yes it is hard to find a house for 7 etc). Just keep putting herself out there this year to make friends outside of accommodation. Join societies, chat to people on course etc. Keep an ear out over the next 6 months.
If nothing comes up then spare room and student pages will definitely have rooms come up and she can go and meet housemates etc.
For what it’s worth a young person I am close to had exactly this last year. I gave her the above advice and told her not to worry or stress. (Inside I was a bit upset for her but didn’t show it). She had a friend she met in first weeks from a fresher event and ended up finding a house with them and another friend for this year (only decided in June and found it this summer.)
It’s perfect now and seems to be going really well. So pleased for her as she was talking of commuting etc and I just kept trying to maintain she just needed to relax and be positive and not stress.