I don't think that the proprietary office suites are needed. The alternatives are good enough for what people do, aren't they?
The problem is that people don't want to change, because it takes some effort. Why would people use WhatsApp instead of Signal otherwise?
There used to be programs that would connect to multiple proprietary systems, like Pidgin. If we had this today we'd have one free-software app for WhatsApp, Signal, and Telegram (and some used in other countries, like IIRC Zangi?). However, the social and regulatory environment changed - now whoever made that app could expect to be charged with a crime.
For the context of this thread, WhatsApp and Signal are both American.
Just look to the federal United States government using it for communicating military strikes, and including journalists.
To the average person, no. If you ask a regular user, you'll find that there is no alternative what Excel can do, the PowerPoint alternatives are missing loads of features, etc. Additionally, files created in MS Office still cannot reliably be used in the open source alternatives without something breaking. Until a non-technical user can open my PowerPoint presentation in LibreOffice and not have to apologize for the formatting, they aren't equivalent.
A huge part of this is fonts. Users prefer proprietary fonts, and when you open files using them in the alternatives it tends to look like terrible. You will not convince users that this is on them to fix, and to be honest they're right, it's not their problem.