Yes, I agree it is not a reflection of the protocols. It doesn't matter either way -- if you have a standard that no one fully implements, your standard is not practically meaningful.
I think partially implemented standards are very useful! You can partially implement in a way that provides escape hatches for users, or you can lock them in to your assumption of the right behaviour.
That said, I think there are very many http clients that implement enough of the standards to me incredibly rich and in line with the spirit of the protocol. The web for humans and machines is based on http. It can improve, but the standard has quite sufficient support to be called practically meaningful
