Here's the core argument of the article, rephrased slightly: housing cannot both outpace inflation and remain affordable indefinitely.
This is not incompatible with some people being able to find affordable housing that is a good investment. All it means is that in the long term - especially when real wages remain relatively constant [1] - these two policy aims are mathematically at odds.
I agree with your rephrasing that housing cannot both outpace inflation and remain affordable indefinitely, but I disagree that it is identical in content to the article's core argument.
This is not incompatible with some people being able to find affordable housing that is a good investment. All it means is that in the long term - especially when real wages remain relatively constant [1] - these two policy aims are mathematically at odds.
[1] https://en.wikipedia.org/wiki/Real_wages