Meh, I don't care about lifespans. I'm probably going to die in a freak electrical accident whilst attempting to set up music gear under the age of thirty, so...
150 years would be about right for humans, if they weren't constantly trying to screw up their world for each other.
I had the capacitors in a 100 watt tube amp discharge while it was in my lap... Stopped my heart for a few minutes. Freaky experience. Lesson number one: Don't work on tube amps while on acid.
When done right, it's no problem. When tripping and in a hurry... Problem. Lesson learned. The hard way. Seriously, I should not have survived that.
if no one had ever created, and you can't create with working on, vacuum tube amplifiers, i doubt very much the transistor would have been invented, or the integrated circuit or the personal computer, or anything that satisfies the distinction between a calculator and a computer (i.e. conditional branching). no radios other then unamplified crystal sets, and only moris code to receive, as no way to modulate, a carrier frequency, or even generate one. that means no tv's nor cell phones either. of course the life span of an individual vacuum tube isn't all that great. comperable to an incandescent light bulb, as they both depend on the life span of their filaments. that was the major reliability obstical to any logic circuitry more subtle then relay logic.
