There are people who don't need to do that. Their use case may be writing the monthly newsletter for the local rabbit breeders club, or writing that novel they've been working on for decades now (and totally are going to finish any day now! I can relate, because I've got two or three of those saved somewhere).
To these people, there are no benefits in upgrading.
(Also, I've spent a lot of time teaching my parents not to open office documents attached to emails, as that has become a popular way for people to spread malware.)
Perhaps so you can open all of those .docx files that people send to you?