I personally had a business in 2007..2011 that replaced windows for Linux. All that time I heard that same old song again: "But but MS Office is so essential!". Turned out, not so much, on over 5000 PCs in several dozen companies.
Update: business eventually failed, for one simple reason - Ubuntu Linux is too freaking stable. The idea was transferring customers to Ubuntu, and have them pay a monthly service fee to do maintenance and fixes. And we have soon discovered that a properly configured GNU/Linux desktop PC can run for YEARS without maintenance at all. Customers had it figured out too and opted to do one-time fees when something goes wrong, and it just wasn't sustainable.