Sure, but there's also a question of bootstrapping. Can you build electronics that work underwater? Sure. But it's a lot harder than building electronics that work on land. The barrier is a lot higher.
Also, simple things like... Primitive humans used tree branches to build lances and things to fight predators. They also used them to dig and to build homes. There are no trees underwater. Octopuses have soft bodies and are not equipped for digging in the ways that humans were, especially without tree branches to help them.
Another obvious difference: one of the key technological discoveries that made humanity happen is the discovery of fire. It would be somewhat difficult to make fire underwater.
Maybe it really is just easier on land. That being said, many species have gone from sea to land or land to sea during their evolution. Not impossible that some octopus descendant could become a land species in the far future... But I have a feeling that evolving bones or a hard shell would he helpful there.
cue movie scene where an octopus, drawn by strange unheard noises, surfaces and witnesses nuclear bombs exploding just above the New York skyline from far away, and the dawn of a new era begins