They could do like NVIDIA and switch back and forth between two, three, and four digit model numbers every decade or so as the numbering scheme gets stale. I remember having a GeForce2 MX400, then a Ti4600, then a 8600, then a GTS 250, then a GTX 460, then a GTX 970, then a Quadro P4000, and now they seem to go for a hybrid scheme where they have the two-digit "16 series" or "20 series" containing four-digit models like 2080 :p