Plivo has useful features that Twilio doesn't have, e.g. Playing in call notifications, bidirectional SIP and IIRC early media. I think Plivo basically copying Twilio's API schema was a mistake as IMO it's not perfect itself. Twilio most certainly should not be resting on its laurels.

One thing I'm happy to see Plivo stop doing is arguably trolling Twilio at every turn. All that did was to indirectly make the conversation about Twilio, instead of Plivo. It's a mistake Twilio has never made, and IMO one of the reasons behind their success.