Online storage is a physical object that requires dedicated infrastructure, whereas software can be built and forgotten about.

Not really, all of those things mentioned need constant security patches even if they don't receive new features. You can't have an insecure Microsoft free application on a non-EOL Windows. They patch things all the time. Sure it doesn't seem like as big of a cost as hard drives, but Microsoft needs to pay engineers and QA guys to fix those programs. Nothing is done for free.