Building a new car doesn't tend to require scrapping an old one. Every car built increases the total supply of cars. Building new luxury housing often (not always) involves tearing down existing housing, leaving the total housing supply static.
The only people that I've heard complain about luxury housing that's not adding more units are when YIMBYs gripe about single family zoning: it's perfectly legal to replace an existing single family home with a far more luxurious single family home without any community input or checkpoints. But more affordable "luxury" townhomes are blocked st every stage by legislative processes that enable single family homeowners to extract ever increasing land rents, when they enforce artificial scarcity. But YIMBYs have almost zero political sway in almost all jurisdictions, and their framing of single family homes as luxury is far from usual.