Not very helpful Philly_Phan. Apple provides a pair of Lightning EarPods with the iPhone 7. Unlike the iPhone 6s & SE, those Lightning EarPods are ONLY compatible with the following (from Apple's website):
http://www.apple.com/shop/product/MMTN2AM/A/earpods-with-lightning-connector?fno de=43e6c9ac722b64b0f1d28d76a9db59c14c0cd…
COMPATIBILITY
iPod touch 6th Generation
And despite some know-it-all's opinions here, this means the Lightning EarPods aren't even compatible with iPad mini 1, the iPod Touch 5, nor the iPod nano currently being sold. They are also not compatible with any Lightning device not running iOS 10.
The 3.5mm EarPods are compatible with all Apple devices, including the iPhone 7 with a 3.5mm adapter. Therefore, any person who buys an iPhone 7, will be getting something less in terms of compatibility than what Apple gave them with every previous iPhone and iPod they ever purchased, without informing them explicitly of the limitations. If that person gave away their old iPhone along with the original 3.5mm EarPods, then they will have to buy another set of headphones in order to use them the way in which you suggest with your simplistic view of this problem.
And finally, your solution involves a dongle, an adapter, or whatever you want to call it. Adapters and dongles and such, are not elegant solutions, nor are they generally intended as a permanent fix. You are suggesting them as a permanent fix in order to use one pair of wired headphones between multiple Apple devices, or anything else.
Regardless, you're saying if they had done a little bit of research, they would have, what? Not purchased the iPhone 7 at all? Not purchased a native accessory to use with the iPhone 7 that isn't compatible with anything else? Learned to live with a dongle/adapter with the iPhone 7? Switched to inferior fidelity BlueTooth headphones, which may have performance problems on some devices? Resigned themselves to carrying multiple pairs of headphones?
Ultimately your advice does nothing to help solve the original, legitimate problem (like a few others here) -- which is how to use Lightning headphones on a Macintosh in particular, and other standardized audio interfaces in general. You're totally missing the forest for the trees here.