The closeness of SD-WAN becomes a real issue for service providers due to their inability to differentiate and the growing competition coming from the same vendors they are reselling. Enterprises are also realizing the risk embedded in the one vendor to rule their network approach of SD-WAN and their inability to adjust the SD-WAN based network to their needs.
SD-WAN is an overlay and therefore has less need for coordination between vendors. Only time will tell to what extent the specifications created by the MEF will be adopted by the industry. The main concern of SPs and enterprises is the closed end-to-end nature of SD-WAN solutions and the vendor lock resulting from it.
MPLS is still pretty commonly used by enterprises, some use it for specific applications while others take it to the extreme and route all traffic of their branches to s central location. Service providers hit a jackpot with MPLS but this is now changing. 2 major forces are making MPLS less lucrative and eventually will kill it: MPLS price is going down; Enterprise requirements have changed