Re: Why (please explain)?
IME the "notebook refresh cycle" is strictly a function of whether parts and support are still available from the notebook vendor. 3 years seems to be typical, though the notebooks themselves will last much longer.
I fail to grasp any connection between hybrid work and the notebook refresh cycle time. One would think the notebooks would last longer if they remain in one place, either office or home. Any damage probably occurs as they are being transported from one place to another.