There will be a successor. When cannot be predicted. What can be predicted is that having laws in place that dictate what has to be used will make a damn mess when that happens.
And for what benefit? We're talking about tiny marginal returns here. Trivial savings, trivial impacts, non-trivial costs to the exposed businesses and consumers, trivial costs to the people who thought up the regulations.
Let me tell you about the "old days" - the late 90's and early 2000's. Every brand of portable device (cellphone, MP3 player, etc) had a different charging port. Very often different devices within brands would require different chargers. Since USB was still catching on, all of the wall-warts and car chargers were specific to each device.
There were brands (iGo) that made changeable "tips" for their chargers... But for the most part, chargers weren't interchangeable. Buying a new device required a new charger, and disposing of the old one.
Is -that- what you're pining for?