Renting sounds like a hell of a deal !!
Assuming 20% down on 1.6M is around $5.5k + tax & insurance, so lets assume that is actually around $7k. Still need to keep up with maintenance and buy/replace stuff, add another $1k, so you are at 8k, not counting the opportunity cost of the down payment ~ 2k/mo.
Easily a $10k/mo. deal. - Renting is sounding better and better!!
Lets say your spend is 6.5k/mo, FI is around 2 Mil. so you are about 1 year away from FI.
If you buy the house your spend will be around 11.5k, so you will need about 3.5 Mil. You will have around 1.4 mil, so you are 2.1 Mil till FI. Lets say you are netting $200k after tax and spending 140k of that, savings is 60k/yr, growth of current investments is around 150k/yr, so $210k/yr added to net worth each year. That will make you around 10 years from FI.
Also to consider, costs about 10% to sell the place, so will need to increase in value a bit just to cover your selling costs.
On the other hand, maybe you work for another 3-5 years, gain a bunch of equity, and are way past your FI target when you downsize to a cheaper area. That is the "everything goes right" scenario.
My vote: Keep renting. Get a nicer place if it makes your wife happy. 4k/mo still sounds like a better deal. (though not very frugal).
Really though - at your income, any of those price ranges are reasonable IF you are going to keep working for another 10 years to pay for it, and you really want to stay in that area longer term (10+ years).
and HELL NO on the 1 hr. commute. Walking distance to work / school / groceries for maximum happiness.