The level of redundancy is a count of the available resources, not the number you can afford to lose.
Depends on your reference frame and interpretation. If you're a passenger, you like to think of three pitots as triply redundant.
If you're a computer, three pitots are singly redundant, since the computer can't decide who's bad when down to two. And if you have five computers, the computers themselves are triply redundant for the same reason.