SCTP, for one, doesn't have any encryption. QUIC integrates a TLS layer into it, in a way that avoids a lot of connection setup time. The best you could do in SCTP is to put it under DTLS, which won't be as fast. Second, SCTP has horrible fragmentation behavior -- NDATA was supposed to help, but didn't make it in. It uses TCP's congestion window system over the entire association, while QUIC also has pacing. And looking at RFC2960, you'll see the names: Motorola, Cisco, Siemens, Nortel, Ericsson, and Telecordia. Generally someone has to pay engineers to make the standards.
As for the article, the UDP vs TCP discussion is a red herring. AFAICT, QUIC's use of UDP is for compatibility with existing IP infrastructure.