I’m not a iPhone X user, but I don’t think AirPods are a reasonable thing to include with any iPhone or iPad at this point. They’re simply too expensive for something that doesn’t benefit everyone (for the record, I have AirPods and they’re great - for me).
Wired headphones continue to be fine for the majority of people, even iPhone X users, and headphones of any kind are a very personal item. The EarPod / AirPod design doesn’t fit everyone’s ears, or meet everyone’s needs. Better to include a basic set and let people figure where to go from there. Plus, AirPods can easily last from one device to the next, so you don’t need to get a new pair every device generation.
A charger benefits a far larger percentage of people, so it makes sense to bundle the cheapest one you can - even if these are multi-generational items, too. The cable needs to be replaced eventually, so you’ll have a spare. Or you can place a backup charger at a secondary location. Or get a stand that doesn’t come with the cable and charger.
A second set of AirPods doesn’t work like that. The best you can do is either sell the new pair (so you didn’t need it bundled to begin with), or try and sell the old pair and use the new one (good luck with that - I wouldn’t buy used earphones).