i was in close relations with telecoms during that timeframe. they went bananas with it because all of it was new for them. so they abused and misused it.

one of them for example used opendailight not for it's openflow capabilities, but via some heavily customized plugin and kind of orchestrator for automation via some crazy yang models that were sent to execution to downstream orchestrator.

but from their perspective and perspective of the management they were doing SDN

traditional network gear had "element controllers". some of the got rebranded into "SDN*something" and got interface liftups

ps. sdn/openflow like you describe were absolutely out of question for deployment in production networks. they could talk about all the benefits of it, but nobody dared to do anything with it and arguably, they had no real need