Some counterpoints ...
Most people don't want to wear the same thing all the time. Our moods often change with the season. People will wear red and/or green in December who never wear it otherwise. Compare the palettes for winter, spring, summer, and fall colors. Most people will choose a few favorite colors to wear all the time. For me that includes black and blue. I wear autumn colors, but almost exclusively in late summer and fall. I rarely wear soft pastels outside of spring or neons outside of summer. Most of us shift over time, and that contributes to the fashion cycle.
Now consider what happens when you go shopping for more than one thing at a time. You probably want to wear those things together. If there's no coordination across designers, you are screwed unless you luck into someone making a whole line that suits your needs. If they coordinate, you can buy a couple shirts here, pants and shorts there, and be fine.
We want people to be able to mix and match, because that requires fewer garments. But it's expensive for a designer to offer a LOT of colors in each garment. Most that do are selling cheap basics. You can find T-shirts in 30 colors, but suitcoats have only a handful of common colors. That means a designer will choose several colors that go together each time they make a new set of clothes. Looking at this fall set again, suppose a designer chooses the Apple palette. A designer might make a suit in the dark red, sweater sets in the four lighter colors, plus a different blouse and a skirt with all five colors in an apple print. That's much more manageable than trying to offer a dozen or more colors at the same time, but you could still mix and match easily. Since they don't want to get bored, designers tend to pick a different subset every year. Next fall's colors might be the Haybale set instead.
Another reason to appreciate the cycle: not everyone wears the same colors. Some years the stuff for one season is mostly or all colors I can't wear. Happens every summer and fall when people choose the "muted" versions: my mother's colors, not mine. Imagine how much it would suck if they didn't cycle and some people never had colors they could wear. >_< It's bad enough that the colors are European-influenced making it hard for, say, African or Asian folks to find good stuff outside a specialty store. There's a reason the African palette looks like this and it's because those colors look better on black people. They're tilted just slightly from European colors.
So here's how to work with fashion colors sustainably ...
Look at the fashion colors that will be popular each season, like Spring/Summer 2020. Which do you like? Which do you wear? When one of your favorites is in fashion, buy plenty of it so you'll have it to wear later. For me that would be Classic Blue. Once in a while I'll spot someone making a line of mix-and-match clothes so I can buy a bunch of things that go together. \o/
Do you see an accent color you rarely wear but enjoy as a breath of fresh air? I like that beachy Biscay Green. I couldn't wear it next to my face, but imagine it as part of a summery print; that would work for me. You can buy one or two pieces of an unusual color and wear them to death while they're in fashion, or more casually if you want to keep them long-term. Think about your neutrals and what goes with them. Mine are primarily black and gray, but I can wear either white or ivory, and some browns. I can't wear the warm, light neutrals. But almost everything looks good with black, white, or gray so I can pick up one odd-colored thing and still be able to assemble outfits with it.
Do the colors suit your seasonal tastes? Saffron is an autumn color for me, not spring; I would want it in different clothes than will probably be offered. Saffron tank tops are useless if I want a long-sleeved blouse, sweater, or velour pants.