Clever Glock marketing strategy perhaps?
Exhibit A: Glock 43x
1st: New model with silver slide which some love, others not so much. Excitement slows down then...
2nd: Reintroduce with black slide option, that covers the colors and when excitement slows down then...
3rd: Reintroduce 43x with light rail (now available in EU), once in US, will likely sell well, when excitement slows down then...
4th: Reintroduce with MOS option (total guess on my part)
A slow roll which markets the pistol in possibly 4 different iterations over time to keep the "buzz" up tempo and has people trading in the 1st version for the 2nd and so on which keeps used market humming along nicely as well. Seems like a clever way to maximize sales of a single engineered design.