Creating solutions for problems that didn't exist
Seriously, some newer devices still use USB mini-B plugs from the 2.x era (e.g. Samsung Galaxy S7). The USB 3.x wider mini-B never really took off aside from external HDDs, and I've only seen the 3.x big-B on hubs.
Going OT here, but take a look at past events here: Mini DisplayPort? Thunderbolt? Apple led the charge and forced further adoption.
New phones are starting to adopt USB-C over the previous universal standard of USB Micro-B (Galaxy S7 uses Micro-B, not Mini-B), but it's still going to take a little while. New standards take time, but what helps is when some of the largest manufacturers force adoption. It sucks at first, this is a given, but that pain will be gone in a year or two.
The Micro-B Superspeed connector (the wide 3.x micro connector you described) was absolutely horrendous and stupendous, I cannot believe that was approved as a standard. Granted, it was never really intended as a mobile standard, but for obvious reasons those cables always ended in a USB-A connector for the host device.
Thunderbolt is still relatively rare, but this is because PC motherboard manufacturers are so slow at adoption. I used to be a big Apple hater, still dislike some practices, but let's not blame Apple for slow adoption of standards by other groups. Apple has always, always, adopted the newest, fastest ports available whenever it made sense. The MBP hasn't been refreshed in design in what now seems like ages, and with USB-C starting to gain ground, I absolutely applaud Apple for making this move. Should they have perhaps kept a few old ports? Maybe, but Intel's new dual-controller support for USB-C connector, allowing both Thunderbolt (and with it, DisplayPort) and USB 3.1 support, is a tremendous step toward a singular connector for mobile devices. It will still take a little while, and dongles will be a pain in the ass, but I suspect everyone will be thanking Apple in due time. But they won't actually thank Apple, they'll just thank the connector gods for finally doing something wonderful. USB-C is going to be THE standard for everything as time marches on, and unlike past connectors, I don't foresee this one going away, ever.
There will likely be a dichotomy here, where desktop and mobile diverge in connector support, but USB-C is really a mobile-first connector through and through. It's a design that finally banishes fumbling with one-way connectors of any kind (any and every connector ever designed prior to USB-C and Lightning), especially in the dark. And this mostly occurs in mobile - rarely are we connecting and disconnecting cables constantly on a desktop. It would be nice for anything and everything to adopt USB-C regardless, and I believe in the end that will happen, but that will take even longer.
But with Thunderbolt and USB 3.1 becoming more of a common thing on the latest Intel CPUs and chipsets, this will happen.
Eventually monitors will support DisplayPort over USB-C, and that'll essentially be the last holdout on connectors for most people. Imagine a time when you can buy USB-C to USB-C cables for everything. EVERYTHING. Well, minus networking. That, likely, will never happen. Too much difference in signaling to allow anything but a dongle or adapter.
A singular connector that can accommodate basically everything? Who the hell doesn't want that?!