Sure, but that remaining 1% is who those 99% go to when their computer isn't working properly.
If people can perform remote admin on machines 1000s of miles away without the need of green LEDs, I'm sure consumer tech will do just fine.
I'd agree that the LED is nonessential with HDDs -- you can just listen; and then you can even make out whether it's doing a lot of seeking or long continuous accesses, but you can't do that with SSDs.