Failiure of competition
Its all down to the lack of effective competition doing something different with the weight behind it
the rest of the networking vendors wokrk in their specific nieches or get floated around between vendors.
Cisco are stifling inovation and holding up standards, as they can't keep up. they are still promoting 3 tier enterprise networks with chassis at the core ffs.
Great ideas from other vendors like extensions to previous protocols, designed to be extended, that solve issues, and dont need new ASICS or another box in your data centre, wither on the vine, as without the standard definition IETF can provide, the rest of the market can't adopt them in an interoperable way.