Management of a large project, like windows, is a management juggernaut - it has tiers of assorted projects/managers/subordinates = all paid and tasked. Apple is the same $$$.
Open source Linux is many projects that various groups get interested in and pursue. Red Hat is a parallel, but smaller, management juggernaut, as they saw this same need and built it.
And there many smaller groups, drawing on the open sources that make sub-types of Linux.
Microsoft spends billions, Red Hat a lot less and all the smaller groups are spare time, or lightly funded.
Want to defeat Microsoft/Apple, add start 10 years ago, add $2 billion/year and a three horse race will emerge