Having created a notable thing is not EXACTLY the same as being notable. Sometimes.

I think a rule of thumb is that something must have been written that was about you, rather than about your creation or whatever. The idea is that as Wikipedia is supposed to be a summarization of the secondary sources on a topic, there should be some material that would fit only in an article about you, and not in the article on whatever you're famous for. Some interesting examples are in the section about “people notable for only one event”: https://en.wikipedia.org/wiki/Wikipedia:Notability_(people)#... (which is not about people who created something and does not apply here! Just mentioning it for what it shows about interesting aspects of their policy.)

I was agreeing with you completely!

Uh-oh - is that confusing? That could cause some problems around here...