Re: Beats me why.
Been working in schools and deploying Chromebooks for 7 years in their thousands. Chances of a device actually stopping working because Google switched it off: 0%. Chances of it being broke in between: 10%. Chances of the Chromebook being deemed obsolete on the asset registers before you get there: 100%
Pretty much any business or school has a 4-year replacement programme for devices like that, so who cares if it stops working in year 5/6/7. But, pretty much, they don't - Google only seem to stop the cheap Chinese junk, they still push updates for anything major-brand.
And given the price of them, I'd far rather buy you a new Chromebook every year than a new laptop every four years.