Yes the 40 is definitely more of a competition caliber these days. I'm sure it will be around for awhile. If I saw a gun in 40 that i liked i would have no issues going for it.
"Many more manufacturers are chambering it" = because it has seen a huge resurgence. Also many more ammo manufacturers are loading for it and up to full strength. While more the case in the US, people like the 10mm because it is versatile and occupies a niche the 40 can't - hunting and high capacity backcountry back up. Even here more and more are using it as their ATC. 10mm is not marketed to the competition speed shooter.
10mm has seen a "slight" resurgence, and many more manufacturers are chambering it in thir guns. But the factory 10mm of the past pushed those 180's & 200's into the 1300+ fps region. Factory 10mm are alot tamer today mostly beating 40S&W by 50-150 fps only.
Frankly, 10mm is over-rated and mostly a hobby caliber that most avoid. Most competitors employ 40 or 9mm.
Where 40S&W comes into its own is when 155-165 grain bullets are used. Sure, the same can be said for 10mm but who gives a #### if you leave your 40 brass behind. Not so with 10mm. And hot rodding the 10mm & a steady diet of hot 180's or 200's will punish your frame.
Light target loads in your 40S&W platform? Yes! Light 10mm loads in your platform? A total waste since 40S&W will do it cheaper in every application.
"Many more manufacturers are chambering it" = because it has seen a huge resurgence. Also many more ammo manufacturers are loading for it and up to full strength. While more the case in the US, people like the 10mm because it is versatile and occupies a niche the 40 can't - hunting and high capacity backcountry back up. Even here more and more are using it as their ATC. 10mm is not marketed to the competition speed shooter.