Your question seems to imply their intelligence increases at the same rate as a human and keeps doing so until they die. That would be very strange if it were the case.
I'm guessing they reach their maximum intelligence well before they die, and then they plateau, like most other animals. So living 20 years would make it more experienced but not able to apply to MIT.
Some scientists think they are quite intelligent animal and they can easily learn. The problem is they have to learn everything by themselves. I read that octopus doesn't transmit any knowledge from one generation to the next one. The mother put some eggs in a cave, protect them and then die once the babies hatch out.
