That's a Stupid home.
I would personally say around the $700,000 mark...is the ideal, cutoff, point of no added gains, benefit and utility.
Beyond that, it's purely for ego and vanity and insecurity and bragging rights. Life at that point becomes rather sad, neutral, unfulfilling.
Ultimately, a living room is just a f'n living room. A bathroom is just a f'n bathroom. A backyard is just a f'n backyard. A front yard and garage is just a f'n front yard and gargage. A kitchen is just a f'n kitchen, regardless if it's a fancier one or plainer one.