Why is SCTP not much used/known

Question

I recently checked out the book \"UNIX Network Programming, Vol. 1\" by Richards Stevens and I found that there is a third transport layer standard besides TCP and UDP:

Answer 1

In reference to all of the comments about commercial routers being broken or lacking SCTP support, the issue is that SCTP with NAT is still in draft form with the IETF. So there is no RFC specification for them to implement it.

https://tools.ietf.org/html/draft-ietf-behave-sctpnat-09