I think it comes pretty close - close enough for probably most but the very largest of users, who, I think, should probably have tried to become hyperscalers themselves, instead of betting the farm and all the land around it on VMware (by Broadcom).
NSX allows you to create seperate clusters which hosts VM's which run the routing and firewalling functionality.
Some things (that were created before NSX) may have come from internet exchanges and hyperscalers, like openflow, P4, and FRR, but were really not missing parts that were required to do software defined networking. If anything, the only thing you really needed for SDN was Linux, and the only real distinction between SDN and non-SDN was hardwired ASICs in the network fabric (well, not hard-hardwired, but with limited programmability or 'secret' APIs).