FSF Philosophy

In the 1950's through 1970's most software was "public domain" which didn't protect against proprietary forks. In the 1970's companies started locking down software with technological DRM.

It wasn't until 1980 that Copyright Law was extended to cover Software. In 1983, Stallman decided to use that copyright law to make sure that software stayed free.

Great history on Free Software here: https://en.wikipedia.org/wiki/Free_software#History

The Free Software Foundation's innovation was to use copyright law to enforce Free Software.