I think that the remark is grounded in some truth. At the very least that people interested in productivity as a main pruchasing factor do steer away (Readability of text and ergonomics are generally sub optimal compared with multiple monitors and ultra wides). "Gamers" do seem to enjoy the immersivity of a TV as Monitors so that might create a whole sub-demographic trying to accomodate both usecases.
From my pesonnal experience, anything above 27'' is sub optimal (windows cannot yet be stacked and the text becomes comically large/small due to macOS scaling).
PS: What has been mentioned above is true, the market for 27" 5k is very narrow and the options scarce. What you are mentionning as far as 27" 4k | 4k Tv's might hold some water. But then you run into the issue of uneven scaling that has been discussed ad nauseam on this forum.
PSS: Don't be rude.