Where's the incentive for people to spend money to get something they perceive as little or no value added? I fear this will be like 3D all over again, or theater quality sound. They may remain niche products, as NashGuy said.
Yes, your comparison to 3D TV is exactly what I've been thinking may happen with ATSC 3.0. I could be wrong, of course. The challenge with 3.0 is that it needs collaborative support from three or four groups to achieve lift-off and succeed: local stations, national broadcast networks, TV/electronics manufacturers, and the government.
So far, the only group showing any real commitment to 3.0 is local station owners (mainly Sinclair and Nexstar, the two largest).
But unlike the previous analog-to-digital (1.0) transition, the government has not issued a mandate that TV manufacturers must include 3.0 tuners or that stations must adopt it. And for those stations that do adopt it, there's no mandated cut-off of their 1.0 signal. Also, there's no government subsidies for tuners/converter boxes for consumers. So the whole thing is voluntary, which isn't necessarily bad, it just means that all the other players have to work together to spur consumer adoption.
As I said, only a very few of the most expensive model TVs from the top 3 premium brands have opted to include 3.0 tuners so far. Aside from that, the only option for consumers right now is the external HDHomeRun Flex 4K (with 2 hybrid 3.0/1.0 tuners and 2 1.0-only tuners) for $200. We'll see if that changes with the 2022 TV models.
As for the broadcast networks, there have been rumors (nothing stated on-the-record) in the past few years that a couple of them (I think Fox and maybe CBS) said they plan to make their content available to their 3.0 affiliate stations in 1080p HDR. (The consensus seems to be that there won't be enough shared bandwidth on 3.0 stations, at least in the next few years, to support 4K, and most 4K TVs do a good enough job of upscaling high-quality 1080p HDR so as not to make much perceivable difference by consumers versus true 4K HDR.) But so far that hasn't come to pass. (And if/when it does, you can be sure that the networks will also make those shows available in true 4K HDR on their own streaming services, e.g. ABC's Hulu, NBC's Peacock, CBS's Paramount+.)
OTOH, the networks have shown at least a bit of support for 3.0 by broadcasting a few of their owned-and-operated affiliate stations in 3.0; Fox and CBS each have a handful of their O&O stations on 3.0 now while ABC appears to have one. NBC doesn't appear to have any yet. Perhaps when ATSC 3.0 launches in the Los Angeles and New York City markets, where the big 4 networks have their flagship O&O stations (e.g. WABC, KNBC, etc.), we'll see the networks step up with more support for what 3.0 can do by making their primetime shows and sports available in 1080p HDR with Atmos audio and perhaps interactive features like viewer polls. Without that level of support from the networks, it's hard to see consumers caring enough about the new format to seek it out.