All of this begs a question…. if you were in the market for a 40 today, what would you get?
I got into the .40 10+ yrs ago because it's what police were using and it had a good track record in the field for working for decades. It's still an effective caliber, but it's going to recoil more and cost more to shoot.
If I'm getting into a .40 in 2025, I'm looking to get used LE trade ins for Glock, Springfield, and S&W for the low price. If I wanted to try something different on the cheap, it'd be the Px4 or some flavor H&K.
There's no reason to bother with budget brands in .40 when the used prices for name brands (Glock) are as low as they are.
More important of a question is why one would get a .40 and IMO you don't want to be all in on just one caliber for a pistol because when the panic buying ever 4 years comes and shortages take hold, the 9 goes before everything else and when it comes back on shelves the price is much higher while the other calibers are still there, the same price they've been the whole time.
It was pretty cool to buy a box of 10mm in 2020 when the 9mm was $50.
Of course that situation can be avoided by having a big stockpile of ammo or reloading, but not everyone has the money or space to do that. In that case, having alternative, less popular, but still common calibers can be a benefit. I still think 10mm is a better choice because it is more powerful than 9, .40, or .45 and can still shoot the .40, but if someone wants a smaller, lighter pistol that still has good capacity and isn't as pricey as .45 has become, the .40 is a good option.