[AdamH12113]

This is not even remotely correct. Historically, Microsoft's biggest problem with Office was having to convince people to buy the new versions since the basic feature set was fairly complete. The file format upgrade in 2007 was the only real forced upgrade since you had to have it in order to read other people's files. I have a copy of Office 2010 that still works just fine and can read files produced by up-to-date Microsoft 365 subscriptions.

The same goes for many other pieces of software. People (especially home users) would buy software once and then keep using it until something justified an upgrade. Software subscriptions were historically a B2B thing and IIRC usually came with support packages to help justify the ongoing cost -- especially important in the pre-internet and early internet eras.

[wkjagt]

I have an old version (I don't remember which one) of Word running on Windows 3.11 on a 486 DX2-66.

[Dan42]

Beautiful. I had that exact computer model 30 years ago.

[bluGill]

Realistically it is close enough to correct. Your old version would still work, but you run into problems sticking with an old version because eventually someone will send you a doc from a newer version.