9mm is just too entrenched in the gun world: translation - millions of guns in this caliber.
Why even bother to replace it? The guns are there, all sorts of ammo are available, the fans are here, the cartridge will get the job done if called upon...so why fix something that ain't really broke?
So the 40S&W has tried and in the last 20 yrs since introduced, it's not likely it has made significant inroads into 9mm territory.
IMO, the lowly, ubiquitous 9mm will be around for a long long time, possibly longer than the 45acp...yeah blasphemy.