Apple

Wow, you really don't deserve the downvotes here. I mean, I totally disagree with you, but the questions are worth addressing...

Apple has really only branded one anniversary product, the Macintosh, which was a flop (for a variety of reasons). I tried to find my previous comment on this, but I doubted there would be an iPhone X and about a year later went back to admit I was wrong, so I could be wrong again, but I was wrong about the branding, not the concept.

With the iPhone X, I believe, the development of the device came before the branding. The branding was an afterthought and not really accurate. The iPhone X was the 14th released iPhone and was announced 10.5 years after the original iPhone was released and even longer after the original announcement.

It seems like Apple wanted to transition the iPhone to FaceID and provide a mostly display front side, but knowing this could face resistance decided to release two iPhone lines (the 8, 8 Plus and the X) , with one continuing the old form and one representing where Apple wanted to go. Think X in terms of eXperimental as opposed to 10.

I really don't think development followed branding, as the goal of Apple is to develop against the competition year after year. Every incremental improvement translates into billions of dollars as consumers choose iPhone over Android, so they don't hold things back, nor are they motivated by "it's the 10-ish anniversary".

The Apple Watch already had its eXperimental transition with the Ultra. It looks like people are going to split between the two and both will be maintained moving forward.

More importantly, the Ultra didn't obsolete bands.

Band specs have slightly changed over the years, and I believe they will continue to do so. Apple may at some point find some technical reason to make a major change but it will be due to something like sensors or other functionality and not just to accommodate a different aesthetic design and certainly not to do so because of a 10-ish anniversary.

To be clear, Apple may call it the Series X and it may coincide with an upgrade that is more significant than what we've seen in the past couple of years (that isn't hard to do), but it won't be as significant as the Ultra and if they do an "anniversary edition" it's going to be something like a ceramic version of the S10 or some other jewelry-like premium edition.