Haven't seen much about .357 SIG lately. Fun concept, not sure it fits the CCW market it was aimed at well now.
It's rarely the cartridge, it's the market and the technology during and after. .38 S&W and .32 H&R have fallen away, but look at the attempts to bring back similar cartridges--just backed by modern metallurgy and bullet design.
.41 AE was probably timing and availability. If it was marketed when .40 S&W was in the pipeline and SIG or Glock had made an auto for it, I could see that they would have given up on .40 and .41AE would have surged.
.45 GAP was a blip thanks to the timing on bullet design. At the time it came around, so did actual good loads in 9mm and .40. Why go for a bigger grip--which GAP was designed to mitigate--and 8 or 10 rounds, now that you could get 15 and17 that would probably actually expand, penetrate deeper, maybe recoil less, and come in a thousand different choices of delivery device?
.40's going the same way. If you bought a .40 in 2002 because it was concealable and effective, good modern 9mm is more effective now than any .40 then and affords you a few more rounds in a lighter, smaller gun. If you want to step up from 9mm, you can get that from modern .45s or the gentler modern rounds in a 10mm, and have the option to move up to something truly devastating.
Many, many things become obsolete because technology passes them by in favor of improving something already more common. Timing and availability just do that to cartridges more often than many other things.