If you buy an iPhone on day 1 from the Apple store you're certainly not getting any gift or discount. With Google you can pre-order and get a $200-300 gift, wait for deals (Black Friday, Christmas, ...) or if you aren't in a rush, wait six months for resellers and carriers to invariably start dumping their stock at half the MSRP. Meanwhile the base iPhone price has decreased by 10-15% maybe.
And I don't see how older MacBook Airs are relevant here. Apple has always sold previous generations of their hardware for years, directly or indirectly, either by actively maintaining production or simply letting resellers deal with old stocks. Google keeping the previous year generation on their product line-up is a very recent development. Not very long ago they would abruptly stop selling the Pixel N before the N+1 were even announced.