Starting by being available for free with source code tapes, and a commented source code book.

History would certainly have taken a different path when AT&T was allowed to profit from Bell Labs work, as their attempts to later regain control from UNIX prove.

Unfortunately that seems the majority opinion on WG14, only changed thanks to government and industry pressure.

Being free was important and history could have taken many paths, but this does not explain why it is still important today and has not been replaced despite many alternatives. WG14 consists mostly of industry representatives.