There are a bunch of private full nodes as well, but yes there are not many full API nodes yet (Hopefully will go up while MIRA matures).
The reason is also that Steemit Inc provides free full API nodes and thus people are not very motivated to set up their own (besides missing financial incentives to do so).

Still, the blockchain is replicated over hundreds of servers. That's what the statement was about. Not "The blockchain is available to query from hundreds of servers".