The 1st-generation Apple Watch Ultra was on the chopping block the day it was released because of its processor.
Although people are frustrated with the lack of support for watchOS 27 on older watches, you have to realize how Apple cycles its Apple Watch processor upgrades. Matt Popovich sums it up quite well:
Apple watch’s main upgrade happens every ~3 years whenever the processor (SiP = System in Package) gets upgraded:
~S4 SiP = Series 4, 5, SE
~S6 SiP = Series 6, 7, 8, SE2, Ultra
~S9 SiP = Series 9, 10, 11, SE3, Ultra 2, Ultra 3
Even though Apple has an S6, S7, and S8 SiP, each one of those have the same CPU and are thus basically the same chip, just renamed. So you won’t see much (if any) performance difference between them.
The takeaway from this is if you’re going to get, for example, a series 5, you’re better off getting a series 6. If you’re going to get a series 8, you’re better off getting a 9. It’s only a one year jump in watch but a ~3 year jump in processor. The processor will be faster and the watch will be supported with software updates for a few years longer.
Knowing these facts, the 1st-generation Ultra debuted with an S8 chip alongside the Series 8 and SE2, and doesn’t meet Apple’s performance standards for running watchOS 27 because it is an S6 chip at the end of the day. Think of it from this perspective - Apple Watch Ultra will be 4 years old this Fall, but its processor will be 6 years old.
The other thing to note is a new chip is released a year before Apple redesigns its mainstream Series numbered watch, starting with the S6 chip:
Faster S6 chip with Series 6 in 2020 - redesigned Series 7 watch in 2021
Faster S9 chip with Series 9 in 2023 - redesigned Series 10 watch in 2024
Faster S12 chip with Series 12 in 2026 - redesigned Series 13 watch in 2027
I like this pattern because each design of the Apple Watch ends its design cycle with the best possible processor at the time. Also note that the S10 chip in the Series 10 was followed by…an S10 chip in the Series 11 and Ultra 3. Apple didn’t even bother to rename the chip because it’s literally the same chip.
The S12 chip is only a prediction, but it makes perfect sense because Siri AI is going to be processor intensive, and Apple Watch needs an upgraded processor designed around Siri AI to sustain the next 3+ years of updates. The S9 and S10 chips are going to support Siri AI, but remember - Apple hasn’t shipped Siri AI for Apple Watch yet, nor demoed it, and currently Apple says it will be ready “later this year.”
I fully expect Apple to ship Siri AI on Apple Watch as promised since they don’t want to go through another Siri debacle, but if you want the best possible version of Siri AI, it will be on the next generation of watches.