I mean, you can definitely fake Dolby Vision. The Apple TV 4K has an option to always output Dolby Vision, and they do their own tone mapping to output normal HDR or SDR content in Dolby Vision. I don't use this feature, and it had pretty terrible reviews at launch (although I heard they have improved it).

But yeah, I think the actual presence of additional dynamic range is pretty noticeable for most well-produced content.