Collagen doesn't even start to break down till 160 degrees, at which point your steak is so far past well done the chef taken out back, and put out of their misery...
Hilarious and I agree. If you order a steak "chef's choice" at a better restaurant it will not be anywhere close to "well done". But I'd only do that at certain restaurants. I've seen some cooks turn medium rare into overcooked shoe leather. I won't call them chef's.
Salt was an extremely valuable commodity before refrigeration as it was a means of preserving meat. Dad used to salt cure a ham from the hogs we butchered. We had a freezer but he just liked salt cured ham.
The stuff from a grocery store may be brined but not as a preservative. When we talk about brining on here we are not talking about it as a preservative. That is a whole different subject.