Good question and many are of course asking it now and will do so until MacOS 15 will be unveiled sometime late summer. Very hard to predict the Apple roadmap beyond that. Mind you, lots of people on blogs trying.
No guarantees whatsoever but worst scenario would perhaps be likely that support with updates for an OS will stay at 5 years or so, so if you are ok with that you could likely run Sonoma with updates under OCLP for 5 years or so if Apple drops intel with MacOS15 and opinions are divided on whether Apple will drop Intel completely this summer.
The last (and only) similar scenario of ending hardware support for a CPU was Apple ending PowerPC in Mac OS X 10.7 Lion in 2011. I remember it quite well. It was pretty sudden and quick but partly because the hubris of Motorola was causing issues for Apple with heat and such. Not the same with Intel so somewhat different scenario.
The latest technologies that need hardware support on the CPU might be a deciding factor with things like H266 and onboard AI on the horizon. Anybody trying to run h265 on a pre-2017 Mac will know what that means in practice
Ah well. So I guess what I am really saying is I really have no idea
What I can say is that I did not think I would be running up to date OS-wise in 2024 on a 12 year old Mac for which official OS support was dropped 4 years ago. So thanks again OCLP devs!