ha. thats a laugh...and a pretty big assumption on your part.
Work in retail at all, you know that is not true.
People buy cheap and super expensive Smart TVs all the time to use the apps built in.
Average consumer does not want multiple boxes and things hooked up to thier tv or have many remotes.
Sure, streamboxes/sticks are popular for those who do not have a smart tv, or have no need/desire to replace thier currenlty working tv, or have a smart tv that is one that is not a full OS like Android/Roku, those tvs like Vizio that have own OS with limited app support,.
15yrs of Retail sales and tech support experince here.
I use Nvidia Shields. Cause i see no need to buy a new 42in smart tv for my living room when the 5yrold Vizio non smart tv, i got for free, still works and looks excellent. Second, in my office, i do not have a tv at all, but a 32in LG computer monitor i share with my desktop computer...and i wish to use that monitor for tv/streambox/game counsel use.