OCLP isn't going to help you run macOS on an architecture it isn't compiled for. So if macOS 16 or 17 doesn't come with Intel code (which is likely), OCLP won't change things.
You’re absolutely right and the reason I don’t consider it a viable option to update my Intel Macs going forward (unless there’s a real possibility to do the same with Apple Silicon machines, which I doubt).
However, if macOS 16 is the first Apple Silicon only operating system (which is a real possibility), that would mean the last Intel macs released at 2019 like the Mac Pro 2019, or the MacBook Air 2019, or the 16” MacBook Pro launched in November 2019, or even worse, the MBA and MBP launched in May 2020, would only get 5 macOS updates: Big Sur, Monterey, Ventura, Sonoma and Sequoia.
On the on the other hand, it is true that many macOS 15 features are already exclusive for Apple Silicon machines, but my guess is, in order to not piss Intel users off, they could make macOS 16 still Intel compatible, at least supporting late 2019 to mid 2020 computers.
And now, I’m heading towards the ARM subforum in order to discuss to what extent it will be justifiable to cut support for M1 or M2 Macs given how efficient and powerful they are.