(It should be noted that for a brief period in the late 1960's, "redline" tires were a thing - serious performance tires were marked with a thin red line on the sidewalls. However, it never took off as a mainstream trend. In recent years, some luxury car tires have been marketed with gold bands on them, but this seems to be limited to the urban markets).
The raised white letter tire lead to the outlined white letter or "OWL" tire which gave the tire company greater real estate to advertise their name and logo. Since the lettering was larger, it was more prone to wearing off if you rubbed up against a curb, which often exposed an entire layer of white beneath the white lettering of a time. In fact, one fellow on YouTube has shown how to "make" whitewall tires by scrubbing off the outer black layer from OWL or RWL tires, although it probably is not recommended by the tire companies.
Of course, the problem with blackwall tires is no one can see the brand name of them, and moreover there is little difference in appearance between performance tires and basic economy tires for mom's old grocery-getter shitbox. Tire manufacturers will have to come up with some new way of distinguishing their tires.
Perhaps down the road we will see this come full-circle, as tire manufacturers once again try to distinguish their brand from others and offer different levels of marketing to different consumers. Again, tires can be made in almost any color of the rainbow, so it doesn't seem that the tire manufacturers have fully exhausted their options yet.
The point is, and I did have one, this is yet another prime example of how we are marketed to and asked to pay more for a product, merely for appearance's sake. Most of us, other than antique car or hot-rod enthusiasts, never cared much about what color our sidewalls were or whether they said things on them. And yet, the majority of us paid extra for whitewalls back in the day without really understanding why we were doing it.
We bought "whitewalls" in the 1940's through the 1960's because we were sold on the idea they were upscale. We bought RWL or OWL tires for the same reason in the subsequent decades. Blackwalls came back into fashion in recent years as "seriousness" and "quality" became selling points for cars. In an era where gas was rationed and cars fell apart the day after warranty, people started to look at quality as an indicia of status. You wanted to look smart by buying a Camry or Volvo - only a doofus would buy some lame American car with whitewalls or RWL tires. Seriousness was the new status in a more serious world.
So maybe colored tires or whitewalls won't make a comeback - unless somehow they can be marketed as upscale, serious, sporty, intimidating, or imbued with some other status hook.