I sure hope that merely not being free, for all uses, forever, would be enough to tank it. Not to hate on Rebol specifically nor people wanting to make money off their work in general but a non-free language is just unacceptable.

I think it was more about it not being worth the money. REBOL was clever and all, but when you do compete with free stuff, you can't just set whatever price you like - it has to make sense for the customer.