If X is Bitcoin, X can't ever be ubiquitous -- the math doesn't work.
Full nodes would naturally become more scarce as the size of the blockchain exceeds 1 petabyte, in no time, making the ideal portrayed in the whitepaper of untold numbers of full nodes a relic.
The inevitable contradiction it always was, when those full nodes are spec'd to host a public copy of every transaction across the entire fucking currency (a regulator's wet dream, btw, and Bitcoin's true innovation).