Agreed... The level of integration across MS products in business is hard to entirely quantify.

NextCloud/OwnCloud and other options can deliver some of it, but all of it is harder... Just email/calendar/contacts is hard to match... Then file collaboration and syncing... And all the corner cases in the various office formats.

Even the non mainline office app, Visio does a lot of things competing apps just don't.

I tend to prefer open source apps for myself, and for code projects, I'll focus on markdown for docs etc... but definitely understand why a corp would just pay the monthly Microsoft tax for all employees.

With the improved web versions, Linux on the desktop becomes an option even then.