Homes have never looked more bleak and dull than today, with blank, smooth, drab surfaces where there should be patterns, textures, and colors. Endless, undifferentiated drywall in neutral paint is the main offender, but people have some conception of what an alternative would look like -- colored paint, patterned wallpaper, wood paneling.
Floors suffer more because the alternatives to smooth beige carpet are further back in memory, and some younger homeowners may not have experienced them at all. Hardwood flooring, the cousin of wood paneling on the walls, is still popular, but many people insist on carpeting to save on costs, to soften the feel under foot, to prevent cavernous echoes, or whatever else.
With the natural texture and grain of hardwood off the table, that leaves colors and patterns to provide visual satisfaction. But who ever heard of colored, patterned carpet?
Millennial homeowners, who were children during the 1990s, may have grown up deprived of examples from the heyday of plaid carpeting. But it may not be too late to get them to replace the bleak beige look they have grown accustomed to, since they're at least used to the trendiness of plaid in clothing. If it looks pleasing on a shirt, why not on a carpet? I really don't care if they do it to be trendy, as long as living spaces stop looking so depressingly lifeless.
Here are just a few examples of how much cheer and charm some plaid carpeting can provide (plus one from the '70s where the only surface that isn't plaid is the carpet -- wouldn't want to over-do it).