Originally Posted by
davidad
If the octalink was such a good idea sealed or otherwise why didn't it last?
Octalink v2 is still around on the lower-end (Alivio, etc) cranks. It lasted longer in the mountain bike groups. And it got replaced because it's strictly inferior to external HollowTech II.
Think of it this way, Octalink is basically just replaces the square taper with a spline interface. It eliminates a lot of the install issues with square taper, but other than that, it doesn't really have an advantage.