This song was written in the sixties. It was a very different time than today. Today, people are technology junkies. Everyone is in love with technology, especially their phone. This song was written at a time when people were rejecting technology, rejecting the system, leaving corporate jobs to live on communes, trying to "get back to the land", "being one with nature", "living naturally", If you think of candles when you think of hippies it wasn't because they were digging on the aromas, it was because they were doing without electricity. They weren't talking solar power. Or wind power. They were talking "People Power". Working on a farm didn't mean driving a tractor, it meant grabbing a hoe. And achieving self sufficiency living as nature intended was the goal. And this was the mindset of the folks Jimi was referring to as "our friends" who "won't be coming with us today". They don't just object to the idea of living underwater on the basis of it's viability, they are philosophically opposed to it because it means being reliant on a piece of equipment, a machine, to breathe. "Anyway, you know good and well, it would be beyond the will of god, and the brace of a cane." A cane is a natural thing made of wood. You could fashion one out of a tree branch in a couple minutes. Folks with a purist ideology when it comes to self reliance and "being one with nature" would have no problem relying on a cane for support. But not machines.