Unparalleled distribution channels? Windows, Word and Excel are core to almost every business on the planet. I was surprised to see the amount of computing that is done in excel in banks.

They can launch half-baked offerings bundled into 365 like Teams that are just good enough to stop people buying the competing product and have 100m users instantly. It's remarkable how bad things like SharePoint and OneDrive are and yet they likely have more users than 99% of B2B applications.

Don't be evil may be ?

Incumbency