It's not really a guess. Anyone who worked with power constrained devices would tell you it's because of polling.
If I told you the biggest culprit is component xyz, that would be a guess.
If I told you the biggest culprit is component xyz, that would be a guess.
I can easily think of a myriad of SW explanations why Windows devices might have worse battery performance than Macs on similar HW that are not "polling": too long of a boot sequence, too many running processes, inefficiencies in the OS kernel in scheduling, memory management or caching, quality of ARM port, bugs in device drivers, bugs in the web browser, bugs in other applications etc. etc.