Sounds like copium against a popular/liked product, seen it with the G wagon and seen it with the Veryon.
If anything, a car being a taxi is only a testament to its durability and (relative) comfort, for e.g, the Crown Vic.
Think about it this way, a Civic, Corolla cross or Peugeot aren't even good enough to be taxi's.
Nobody wants to willingly get in the back of a Civic/City in place of a Camry/Accord.
Plus it's the E class that is used as a taxi, from the 124 all the way to the 213, the model of Mercedes which many consider the only "real" Mercedes below the S, and that doesn't change the fact that people still lust over it, just like the Sonata in pk. I mean, my mother out of all people said that the Sonata doesn't just "move" but "floats" when one was passing by.
Not that any of this matters, but this taxi argument is just pathetic and lazy imo, its literally the exact same as saying the G wagon isnt incredibly capable or the Veryon wasn't an absolute feat of engineering just because you only see rich people drive them around city centers at 40 kmh. And yes I will draw a contrast between a Hyundai and a Bugatti, and yes maybe I do have too much free time.