Not everyone is a Linux user, or willing to become one.
You can install Ubuntu on 100 Thinkpads and have that be the official OS of your company.
The tech folks will love it, but Mr Smith in accounting will be angry and confused. QuickBooks doesn't work, how will he get anything done ?
He doesn't want an open source alternative. He wants QuickBooks.
This is absolutely on point. Every time Microsoft comes up, HN thinks you can just replace an orgs 30 year old stack with OSS. It's ridiculous and shows the narrow experience of this crowd with their small teams.
Linux still doesn't have a lot of one to one equivalents for Microsoft software. If Mr Smith in accounting likes using QuickBooks and Excel, you can't just tell him it's time to switch to libre office.
I definitely think Linux is better for personal usage, but I don't expect most companies to ever realistically roll it out to every desktop.