What I see here is an evolution away from proprietary connectors (but I definitely agree that they strongly favored such connectors in the past). By the time of mini-DP and Thunderbolt, Apple and Intel were working jointly and the technology came to both PCs and Macs. By the time of USB-C, it was basically the entire electronics industry working together with Apple, and the end result has come to just about every kind of electronic device made by nearly every vendor. It doesn't get any less proprietary than that.

The bizarre part of the USB-C story is not Apple's involvement or early adoption of it, but rather that the mobile hardware side of Apple refused to support it. That they clung to the Lightning connector until the EU forced them to drop it, while their computer division had long since and enthusiastically adopted USB-C, is much more damning.