Hmmm. I'm not so sure you can extrapolate that from those examples.
A 2011 and 2016 aren't the same platform. The earlier models were Titan based, the later models are Patrol based.
I'm not sure Lexus depreciation is any better or worse than Infiniti (my $82k car cost me $5k - 2011 with 90k miles).
Depreciation on luxury vehicles (especially ones that get 13mpg) is dismal, regardless. In 2 years, that QX will be worth $18k.
At the end of the day, buy the car you like best, and know that you may lose all of your investment (it's a depreciating asset that will, in short order, be worth $100 in scrap steel).