"change half the network" doesn't meet any definition of democratic access to power that I am familiar with.
People don't need to do a turn on a garbage collection route to vote on how their municipal garbage service is run.
"change half the network" is almost the textbook definition of democracy.
I think the main problem with bitcoin is that it doesn't scale, because every transaction has to be approved by the entire network. More payments and a bigger network means the number of validations goes up quadratically.