Why would it be counted differently?
The GB and GBC were counted together.
DS and DSi
PS4 and PS4 Pro
Xbox One and Xbox One X
3DS and New 3DS

They're the same system just updated specs and capabilities.

Alright I give. It should count.

You do realise that nearly all sidecars are one wheel

If they have the same architecture and play the same games, they are just different SKUs of the same platform, whatever the price and power differences, so yes, they must be counted together.

Same platforms so why shouldn't it be considered the same? Same eco system, same services, same library, same accessories, only difference is power.

It depends on what you're trying to assess.

If you were trying to assess which company was more successful, then it would make sense to include Series S. There may be other circumstances where it wouldn't make sense, but I can't really think of any.

Yes.

If it does the same games, looking the same (except in resolution), then its the same gen device.
The only differnt is the amount of gpu compute it has, between it and the series x.

Here's something to chew on.

If Lockhart is basically an XB1X in terms of performance, perhaps slightly more capable because of updated tech, does that count towards next gen? Would XB1X count towards next gen because of it's performance? Could SNY just take Pro, slap a Ryzen CPU in it, or give the GPU 54CU's, and call it a PS5, even if it still looked like a triple cheeseburger?

Where is the line and when is it crossed exactly?

I do understand why in some ways it would make sense for Series S and X to be counted together, but that leads to future concerns, like what if by chance we get another mid gen XB upgrade? Do all 3 count towards next gen sales at that point? What if they just keep adding letters to Series models for the next couple decades?

I can't say yes or no at this point. Sorta depends on what exactly Lockhart's capabilities are, but even if it outperforms XB1X by a smidgen, I don't know that just because it has updated tech, that it should automatically make it next gen.

Yes because there's more to it than just slapping Ryzen. Series S will have Nvme SSD vs traditional hard drive. Series S will have next gen RDNA 2 technologies like Ray Tracing, Variable Rate Shading, Mesh Shaders, Sampler Feedback, Direct Storage and etc vs none of that. And the list goes on.

Resolution and Teraflops is just one aspect of the bigger pie. You build a game around those technologies and SSD and you run it on a Xbox One X with Ryzen and mechanical hard drive and see how much of a power point slideshow at 540p it will be compared to the Series S.

So a decade from now, if we get a Series Z, 36TF, and it's no longer Ryzen or RDNA anymore, and we've moved beyond RT, does it still count towards XB Series model sales? What if the Series Y that releases alongside it, has all the new tech and features as well, but is only 10TF and $199? More XB Series model sales?

It's not all that clear cut. That's not to say it can't be counted towards Series sales, but it's all of the reasoning as to why it should or shouldn't.

*What if MS had another secret, and XB1S was also getting a super slim upgrade with XB Series tech, though the same performance and same XB1 name? Where should those sales be counted towards?