There is ZERO discussion about which is toughest.
Google "Glock 21 torture test" for the quintessential handgun torture test of all time.
The 21 is a .45, but the only difference between it and the 9mm versions is parts dimensions. Find and read that test, and you'll know for yourself that there is ZERO discussion.
I find the idea that there is ZERO discussion about any topic on the planet to be relatively ludicrous.
I own, carry, and use as home defense pistols Glock 19s. I have no qualms about their "toughness". That said, my experience is Glock has made a concerted effort to prove their toughness through marketing and that far more people have conducted endurance tests with Glocks than a number of other pistols (I'd wager any other pistol). Not a lot of folks have the money to put tens of thousands of dollars worth of ammo through a pistol on their own and not too many manufacturers make a concerted effort to demonstrate that to the public. I don't argue that Glocks aren't "tough", just that more people have made the effort to prove them tough and it might skew our view.
I'd also wager that toughness starts to become relative. I use Craftsman tools. For me they're tough enough. Now that said, I know mechanics who use Snap-On tools because they can go through Craftsman tools like toilet paper and despite the free replacement they need the tools to work when they're on the job. Now if my tool breaks and I have to drive to Sears it's no big deal, but it's not my livelihood. This isn't me saying that toughness is unimportant. What I am saying is if Pistol A will go 60,000 rds before breaking and Pistol B will go 100,000 rds before breaking but I'll only ever put 20,000 rds through the pistol, is there a real noticeable difference? Now we obviously have people on this forum that will eclipse 20,000 rds in less than a year. But I often see "toughness" brought up and I wonder if people aren't getting ahead of themselves. Even a measly 20,000 rds at $0.20 a round is $4000. 60,000 rds is, you guessed it, $12000 dollars. I can buy a decent used car for that, and if you put $12,000 worth of ammo through your pistol, odds are you could buy a new pistol.
In my opinion if you do the recommended upkeep from the manufacturer just about any pistol will prove to be "tough". Be mindful of your own demands on the tool and be realistic about what you need from it.