The problem isn't plain MS Office (Word, Excel, PowerPoint). The more nefarious set of issues is around domain-specific software that is only compatible with Microsoft platforms and software.

For example, Veeva Vault is the industry standard content (and content workflow) platform for life sciences. It's a heavy, somewhat unpleasant platform similar to a Workday or ServiceNow, but it's ingrained and it compliant with all life sci regulatory bodies' regulations. It requires customers use SharePoint and Office under the hood.

Things like that can't just be ripped out and replaced because there are no FOSS options.