The developers of LibreOffice made a conscious decision to make their product look and feel like Office, since one of their goals is to help people learn these suites for functional skills, so their learning would then translate to the predominant package. I have this first hand from a conference.

Then of course Micorsoft created their ribbon UI and enforces protection against others copying it.

Personally, I don't find the ribbon intuitive, and others, perhaps a majority, feel the same way, but Microsoft has all that weight behind them.