Possibility of just getting ghosted by a uni ?

I've been waiting what feels like eons for a reply from Edinburgh (they only have like two weeks according to their own deadline to get back to me) and it got me thinking about my friend who got to the interview stage with Cambridge who then just never replied (I assume there was some kind of quiet rejection or something but Idk). Could they simply just not respond and let me get on with it or is it mandatory for them to send me a response ?