Yeah I know. I used to build houses and also remodeled/flipped a few. It just annoys me when people trot out that line of BS.
The "cheap" factor for houses today comes in the finishes. If you don't actually look around and employ good design you wind up with cookie-cutter stuff, which is what builders do on everything not custom. The other side of that is that many finishes are so much more attainable and just not luxury the way they once were. Technology and manufacturing have made things that required a craftsman/artist very easy to get at low price points. And then absent a legit interior designer people slap together a hodgepodge of these luxury items without rhyme or reason. Architects have also seemed to have lost their damn mind and do some ugly ass shit to houses. It's like they give very little thought to exterior design vs interior sqft.
But, none of that makes the houses worse/cheaper in terms of construction both for the guts or the finishes. It just means that a lot of tasteless and ugly shit gets built.