I'm sure that many can make the same claim. In the 1980's, I was an operating systems architect working at IBM. I thought up many interesting (to me) innovations while working on the first couple of releases of the AIX on the IBM POWER hardware. It was a great job and I learned a lot doing it. I got to work with some really brilliant developers and computer scientists (a number from IBM Research).
One project I was responsible for was the development of a distributed file system for AIX. The goal was a distributed file system that addressed some of the weaknesses found in other distributed file systems at the time. Our chief competitor was Sun's NFS distributed file system. NFS was a really nice design. It was well integrated into the operating system and quite reliable because it utilized a (mostly) stateless server. This had a number of performance and security implications along with some file system semantics over NFS that didn't match local file system semantics. We wanted to introduce state for the server to address these issues and thought of a number of complex protocols to manage it in the presence of unreliable clients. That's when I thought up the idea of making the clients keep their own state to be restored when they reconnected to the server. I protected this state from manipulation by the client by encrypting it. I didn't call them cookies, I called them tokens.
This design was patented by IBM and I was one of the two inventors on the patent. This patent was owned by IBM and years later they gave a special award for this patent because it decided that it was one of IBM's most important patents. (They wouldn't have done this unless the patent had held up to scrutiny or legal challenges). Unfortunately, by that time I had already left IBM to start my own company--I was at the top of my game and had confidence that I could create a software product of some kind that would be successful--so I missed out on the financial award for the patent. By then, I was at my new company and already in competition with IBM.
By now, the patent should be long expired. Interestingly, IBM ended up buying my company around seven years after I and a partner started it.
I was very aware of the academic literature and industrial practice during this time so I do believe that my invention does reflect original work that ended up with a very significant impact.
From a more personal perspective, the invention didn't financially benefit me. The work that I did at my company own was more creative, inventive, technically impactful, and financially important to me. For example, Austin Ventures has indicated that my company was the start of Austin becoming an important high-tech location, but none of that was related to the cookie.