The key for us in the UK is how effective are our immunity going to be against this new variant. I strongly suspect that Pfizer, and the experts already know because they have sequenced the virus. Once you sequence the genome, then you know the primary sequence of the protein that follows. And when you know the sequence of amino acids, you can predict the confirmation of the protein and then you can model whether antibodies will still bind to it. When they say that they have done desktop studies, that is what they mean. Then they have to move from 'in silico' to 'in vitro' and that is when they will know for sure.
I am hoping that the booster vaccine will hold off serious infection and then that will allow is a window to develop another vaccine, if it's needed. It has been reported that Valneva is due to deliver a whole virus inactivated vaccine to the EU in the 2nd quarter of 2022 and Pfizer, Moderna can develop new vaccines in 100 days. So we should be OK.
IMO we could have developed boosters and vaccines against Delta but the pharma industry did not bother because they knew another variant was on the way and it just wouldn't work producing a new vaccine every 6 months. People just wouldn't take them.