Ok, I can see, intellectually, the argument against .45gap--that was a round that made as much sense as an "improved" .280
However, given that there are people still shooting 9mm largo (and various kinds of 9x23) .32 french longue, 8mm nambu, predictions for vanishing are slim.
Obsolete just does not mean out-of-production, not with ammo. Firearms are durable goods and last and last.
This is absolutely correct. I know more people than I can count on both hands that still regularly use guns older than me(1977) for personal protection and hunting. Most are still common calibers but certainly not all.
That same point is why the 30-30 is still around and will be long after I am dead. They made so many of them and they were generally speaking so well made that they will kill deer for another century. When you apply that to .40 especially or even .32 and .25 there are too many guns out there to pretend they will go obsolete.
Obsolete cartridges only happen when gun manufacturers don't produce guns chambered in the cartridge. And even then they are still often made in limited production runs for decades(see .375 Win)