Purely speculative discussions are my specialty.
There are conservatively 6 more times frames before we even get up to the present day where Desmond is. They would be stupid to jump from Ezio to the present, there is too much more story they could play out.
Honestly, as long as they keep the story moving, and they don't got MW2;WAW;BO on the franchise, they will find me waiting in line for each installment.