Not sure about other phones, but ThinkPhone 23 was supposed to get Android 16 anyway

https://www.androidauthority.com/lenovo-thinkphone-hands-on-...

I have a 'long life' Android device (Zebra EM45) that has only recently gotten its Android 15 updates; its committed through Android 16 so I assume it's also waiting on Qualcomm to get its act together and in gear for whatever final patches are required for the QCS5430. IIRC, QCOMM is promising "10 years" on the CPU.