You are comparing a 2014 phone (iPhone 6+) to a 2017 phone (Pixel 2), and are surprised that one seems 'better.' It's obviously not even close to an apples-to-apples comparison though.
For that reason, I didn't give attention to the device's speed. 95% of my comparison is the current iOS (which the 6s+ runs) vs. the current Android.
Because I'd push back on that.