Apple’s next WatchOS will not run on the original Apple Watch, which means it’s about 3 years between new hardware and obsolecense.

This is interesting, as the original Watch was sold more of a luxury item, with the top end model being made of gold, and costing upwards of £10,000. Unlike your Rolex, your Apple Watch will have a much shorter shelf life, and (battery degradation being an issue), will eventually fail in a far shorter time than the mechanism in more traditional watches will.

Isn't this true of all Apple products?

Gen 1 always has the shortest lifetime.
Take the ipad 2, lasted until the last iOS update I think (something like 6-7 years)

The iPad 3’s last iOS update was iOS 9, which was released in 2016, so you got about 5 years worth of OS updates for it. They pretty much retired all the 32bit processors about with that, so the iPad mini only got 3 years as it’s support ended with iOS 9 as well.

I left an apple on the sideboard at home.
Within a matter of days it was full of bugs and rotten to the core!