Here FS tells you why buying a 4.5M house is nuts.
Here’s a good way to look at your down payment:
The $2 million downpayment is guaranteed to earn $62,000 a year in state tax-free income if it was invested entirely in a 10-year government bond. Hence, one could easily argue that the total annual cost of owning this house a year is not $223,254, but actually $223,254 + $62,000 = $285,254.
My bar is lower than FS’. For me anything over 2M is no-no.
Are you going to let your Millbrae / Burlingame dream go away? Or you think they will come under 2M in the future? 
Maybe I can stretch it to 2.2 or 2.3…
Most millbrae houses I’ve seen are between 1.6 to 2.4. So under 2 is doable. Burlingame though… 
This table is more useful than the absolute price of the house. Some people can buy a $4.5M house, and it’s low percent of gross income. Personally, I think it makes some sense to stay in the under $1.2-1.4M range where homes are the most liquid. Granted, I think that range keeps moving up, but you can usually see based on DOM where the price is that homes start to sell slower.
What an idiot. He should follow his own advice.