A typical windows laptop has a DRAM footprint (mostly because of the AV scanners that everything has installed) rather higher than a ChromeOS box, even with the browser running. And the storage requirements aren't even in the same ballpark: something like 40GB for a routine OEM windows install vs. 6-7G for the ChromeOS boot image (last time I checked, anyway). Add to that the fact that most of the chrome apps are optimized to store to the cloud instead of relying on local disk, and the chrome box can skimp on memory and storage (e.g. a $8 64G eMMC chip instead of a $60 256G SATA or M.2 drive) in ways that windows can't.