Tbh the only reason I can't put an ubuntu for my parents/grandparents is Microsoft office.
Libre is generally ok, but they deal with lots of documents from different ppl/orgs that just need to have similar rendering. Windows is so bloated it's insane
Office in the browser works really well, in my experience.
The rendering won't be 1:1 but installing the most common MS fonts already does a lot
Even Microsoft can't perfectly replicate MS Office rendering. Despite access to the source code. Lots of stuff renders slightly broken in the web version, especially once headers and footers are involved
As an individual that makes MS Office hard to replace in the workplace. But maybe entire agencies switching over will have enough weight that they can force everyone else to adapt to them