Even if you purchased - this year - a new Apple Watch Series 4, a new iPad Pro and new Mac, your new watch will be locked into an outdated version of WatchOS, unless you purchase a newer iPhone.
What other products you purchased has nothing to do with it. That is a staw-man argument.
You Apple Watch will still do what it did yesterday, tomorrow. And when you decide to upgrade to a newer iPhone, the Apple Watch will be ready to upgrade to watchOS 6.
This fact was not clearly disclosed during the Apple hardware or WWDC keynotes, at Apple Stores or by authorized Apple resellers.
https://www.apple.com/watchos/watchos-6
at the bottom of the page. And WWDC keynotes are already long enough without covering every detail of every product announced. As for authorized Apple resellers, that is on them if you told them what iPhone you owned.
The new iPadOS 13.1 can be installed on iPad Pro without the newer iPhone purchase requirement.
The iPad is Not an iPhone accessory. The Apple Watch is an accessory and dependent on the iPhone. Maybe in a few years, the Apple Watch will become powerful enough to stand on its own and become a real "Dick Tracy" watch. But for now it is an iPhone accessory.
Apple could resolve this issue by allowing iPhone 6 and 6 Plus to install the latest version of iOS 13, or an updated version of iOS 12.4.1, if only to enable new WatchOS installations for recent Apple Watch customers.
Yup. Suggest you tell them.
Apple Watch Feedback
https://www.apple.com/feedback/watch.html
Just wondering how far back should Apple provide watchOS 6 support?