If he doesn't know, no way grandma and grandpa are going to be able to get him a birthday present.
The kids may know and understand this, but parents may not. If you go to a store today, you will only find the latter two, and you won’t have an issue picking the one your kid asked for (i.e. the X). But when both generations were on sale, the parent might end up buying "One X" instead of "Series X" because it’s cheaper, or buying "360" instead of "One" because it’s clearly bigger (by 359 no less).
The Xbox line-up is just comical. I walk through any gaming department and see an "S", "X", or sometimes even both "S" and "X" on Xbox games. If it was just "Xbox 7" and "Xbox 8", you'd at least have some idea of what's going on.
It's like someone who knows nothing about cars trying to figure out SE vs LE vs CE vs XLE trimmings when looking at accessories.
Wtf, there are two different S's and two different X's? I thought 'Xbox One _' and 'Xbox Series _' referred to the same products.
I don't know a single kid that would not know which models are current gen and which are better or worse. Argument about non technical parents is valid but any kid today will know which Xbox to get and will tell their parents. Kids these days know much more stuff than you seem to think, they spent 1/3-1/4 of their lives on the internet. My 11-12yo nephews built PCs just following youtube guides, they do video montages of their Fortnite games to put on youtube and almost every single friend of theirs is similarly familiar with current tech.
Xbox having lower numbers is purely fault of PS dominating the market over last decade, people will continue buying it cause they trust Sony to deliver exclusives and they have existing game libraries. I converted two Sony fanboys to Xbox with Game Pass and they both love it. Noone these days buys a PS "because they are confused with Xbox naming", 5 minutes of googling answers any questions. The only people who might really have an issue with this are boomers+ who are not even going to buy a console for themselves cause "games are for kids and a waste of time".