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

Reading the SCTP Wikipedia page I'd say that the main reason is that SCTP is a very young protocol (proposed in 2000) that is currently unsupported by the mainstream OSs (Windows, OS X, Linux).

If "very young" seems inappropriate to you, think about IPV6: "in December 2008, despite marking its 10th anniversary as a Standards Track protocol, IPv6 was only in its infancy in terms of general worldwide deployment."