RSA was once just an idea without an implementation. Would you say it was worthless? Why was it published then?

A defined specification is very different from an idea. RSA is a perfect example. I would say the "idea" here is public key cryptography. It was total genius when it was invented, and 99.999% of the world didn't care a lick.

Once it was implemented in several crypto systems, including RSA, and people started using it, the value became clear.

> Why was it published then?

Was the publication sold to anyone? Why did Ron Rivest, Adi Shamir and Leonard Adleman decide to create a company using the concept rather than just sell the publication itself?

I think you just proved my point.