The sliced bread might not be the best quality, but it is rather consistent and much less crummy when making yourself a toast or just butter+jam. No dangers of a kid cutting itself while making its own sandwich either.
Middle class people who think of cooking for themselves as a hobby maybe lose the ability to understand labor-saving technical advances. People who cook as a duty think of cutting bread as more work, which it quite obviously is.
If cooking is a hobby for you, you're seeking labor. Maybe that makes the obvious unintelligible. If you're poor and have a bunch of hungry kids waiting, you don't want the cutting board covering up half your counter space while you're carefully trying not to screw up eight slices of bread before something on the stove burns.
It was combined with the toaster and sandwiches made easily, and taken away for a bit in WWII, and then came back. It was one of those advancements that "stuck".
Knew what absolute disaster of a video this was going to be before clicking. Highly recommend watching Colin's videos, this one included, for the sheer level of "this is clearly a bad idea, let's do it" that he gives off and the things learned along the way.
Can someone explain to me this analogy? Because I consider sliced bread as decline. But maybe that is cultural thing.