Lo Pros, Represent

But I've always understood that, above seven speed, big/big resulted in death-by-trashed-drivetrain if you use it more than "accidentally"

You have to remember that old-school testers who worry about such things will have been brought up in the days before Sedis brought us cheap and bendy bushingless chains in the late 70s. On an old 6-speed block with a stiff, bushed, Regina chain, especially with the ultra-short chainstays which were fashionable in the 1970s, you really could tell when the drivetrain was being pushed to its limits. With modern kit, 1×10 or 1×11 works just fine all the way across the cassette as long as the single chainring is lined up roughly in the middle, i.e at about 42-43mm for 130mm OLN road or 45-47mm for 135mm OLN MTB