I'd like to call your attention to the section of this article that argues against what you're saying. ". . . one era's luxuries are another's commonplace good

I'd like to call your attention to the section of this article that argues against what you're saying. ". . . one era's luxuries are another's commonplace goods. In short, the negative positional externality is often compensated by the public goods of infant industry effects and research and development." The negative externality view of positional goods seems to be a minority opinion among economists. The examples of positional goods in the article were further quite marginal and it would be difficult to assess what part of the good is positional (and thus deserving of a tax to mitigate the externality) and what part is just valuable.