A company called "Dana" made crank-mounted 10-speed internal transmissions for bikes in the 60's and 70's. They also had a 3-speed that was more popular. I had

A company called "Dana" made crank-mounted 10-speed internal transmissions for bikes in the 60's and 70's. They also had a 3-speed that was more popular. I had an opportunity to work on one in the early 80's, similar to the one pictured in Fred DeLong's seminal book on bicycle repair. It weighed a ton and was extremely labor intensive. Granted, we have access to better materials today, but the cost/complexity cannot compete with the weight, simplicity, and rapid repairability of chain+derailleurs.