This is a perfectly succinct way to put it.

New housing is simply more expensive; so it's marketed as "luxury", and it's sold at a premium to the higher end of the housing market. This reduces demand for the older, more affordable existing housing stock, and with depreciation and wear and tear, the new housing will become more affordable as time goes on.

If you're in a market with a shortage of housing, those with more money will simply outbid those with less, even for older, less desirable housing. I've seen it, where when I moved out of my last apartment before I bought a house, my landlady raised rent considerably when looking for a new tenant, and even then she got a tenant who wanted to pay her over the rate that she was asking for to ensure that they were able to get the apartment over all of the other applicants. Wealthy empty-nesters who were downsizing, and willing to pay a premium for an older apartment in a desirable neighborhood, forcing out anyone who might have otherwise been able to afford it.

So yes, while it does help for there to be some push to build more affordable housing, if taken to an extreme building only luxury housing will leave an unbalanced market, in a lot of cases building luxury housing is exactly what you want to do to reduce the competition for the existing, more affordable housing stock.