Good Information and suspicions confirmed . .
However . . .
Empirical evidence shows that the greater the differences in hardness of two "Conflicting" metals, the less likelihood of "Bi-Metallic Galling" occurring. The catch to all this is "Adequate lubrication", because the softer metal will gall almost instantly once the lubricant is removed for ANY period of time . . The Crankshaft/Bearing symbiosis is one such example.
This phenomenom is why the cam manufacturers can use softer metals in their camshafts when solid or flat tappet lifters are used. You'll notice that the hardfacing is very adequate on the Roller cams and the differences in hardness between the cam and the roller faces are closer together, although still not the same. Oddly, metals of the same hardness will gall quicker than those that aren't when put together . .
And . . Back when many of us used magnetos for our ignitions, the turning resistance on the cams when using engines with a Mag/Distributor driving off the rear of the cam was a lot greater than it is today with the "Smart Ignitions", where all you're spinning back there is a rotor. This caused the cams to actually twist, retarding both your ignition and the valve timing. Not to mention in many cases, total camshaft failure. This forced the cam manufacturers to use billet stock for their products and many of us became "Spoiled" because we got camshafts that rang like a bell when tapped with a wrench, were hardfaced and NEVER wore out . .
We don't need cams that tough anymore. And in most cases, if a cam and lifters are pre-lubed when the engine is put together with a good anti-seize, and you build oil pressure before you ever spin the whole engine, You'll never "Wipe" a cam lobe. But, it happens more than it used to because the cams certainly aren't made of the same stuff . . And our spring/valve seat pressures are so much greater.
The Comp Cam we're using in our 582 right now has about 250 passes on it and it's "Brand New" . . Of course it's a Roller so it should, but we did wound one when a lifter failed a couple of years ago. And it didn't take long! Just about half a pass! Looked like you took a Parting Tool to it! But it ate the roller too.
Bottom line, yes, some cams aren't as hard as others, even from the same manufacturer, but for the most part, they're pretty damned good when you look at the RPM, the seat pressures we ask for, the lift and duration of the cams and the frequency of use, as well as the cost.
We weren't doing what we do now only 20 years ago . .
Need to make a correction . . We have just a little over 150 passes on that cam . . . That's about 40 miles! Time flies when you're having fun!