Saying there "should' be a market for full-suspension road bikes is irrational. There is no market---no demand---because there is no great benefit to the product compared to existing products, and there are significant downsides.
Unless once considers stuff like Future Shock to be "suspension" .... the amount of travel needed to smooth out most paved roads is minimal, but even a little travel is heavy. Since riders provide the motive power (unlike with mopeds) that extra weight is felt immediately---and the people who ride paved roads daily, like commuters, probably don't want to waste any energy unless they are getting a significant advantage---but as we all know (if we ride roads) we generally don't Need suspension.
Sure, a Cadillac ride would be wonderful ... but the old, plush Cadillacs had big, whopping motors and could not corner well at all. Most people who ride on the road to commute don't really want suspension---else there would be a market, and they would constitute that market.
Most recreation riders don't want suspension, and in fact want light bikes.
The only type of rider who would want suspension would be the very relaxed recreation rider ... the low-speed, around-the-block, or ride-the-local-MUP-slowly folks .... and some of them have hybrids with front suspension. The logical disconnect there is that at low speeds, bumps are minor, and for people riding quickly enough for the bumps to matter, they would generally to lift out of the saddle for "suspension" and keep the bike light.
There is simply not a large number of people who are willing to pedal hard to pull the weight of full suspension, at a speed where suspension offers a real benefit, and even for fast riders, most don't ride roads bad enough that suspension is needed at any speed. (There are dedicated gravel bikes with suspension forks, but that is a different discussion.)
There is no "market," because the benefits of F/S are negligible at low speed or over mostly smooth terrain (bumps lower than dropping off a curb, for instance.) F/S is great when taking bigger hits, but not many road riders are regularly hopping curbs or tackling obstacles similar or larger. Sure there are some---and they tend to ride BMX bikes, or "urban assault" bikes, from what I see.
The benefits of F/S simply are not sufficient for most rads and for most riders ... hence there is no market, no demand, no pool of customers. And the few who Might be potential customers seem to be fine with front shocks and fat tires.