The reality is that lots of popular places offer late. They make a tranche of offers and then are waiting to see patterns of people firming, insuring and rejecting them, before they know if they can make further offers.
DC might not want to wait, but it’s that or firm somewhere Elise and essentially withdraw their application from where they are waiting for. People doing this, also allows unis to get a clearer picture and make decisions about further offers.
Few places, especially top ones offer genuinely first-come first-served accommodation now. You might be able to express preferences, but many won’t confirm accommodation details until after results.
And there is usually no particular benefit of firming early rather than waiting ….and especially if you haven’t heard from everywhere.
The longer you wait, is usually an indication of how competitive the course is. Unis are balancing their figures based on previous stats about how many candidates will firm offers, meet their offers, etc etc. It’s very complex and info available to them evolves as time progresses through the current cycle. That’s why it takes so long. It’s not just administrative inefficiency but the business need to make offers so that their course is as full as possible (but not over full) come results day and that they can be sure they either won’t have to go to Clearing or need Clearing for v few places. Remmeber, they can make you an offer, but they don’t know where else you’ve applied and if you will firm or insure or turn down.