Well, you don't recall correctly
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The non-TB model of the 2016 & 2017 13" MacBook Pro has just 2 USB-C/Thunderbolt 3 ports to begin with while the TB model has four of them, two of which (the two on the right) are limited in PCIe bandwidth (see
https://www.macrumors.com/2016/10/28/macbook-pro-tb3-reduced-pci-express-bandwidth/). On the 15" MacBook Pro all four ports offer full PCIe bandwidth.
But even then your statement still doesn't make any sense since you're mixing up USB-C and Thunderbolt 3. USB-C is only a specific connector, like USB-A, USB-B, or MicroUSB. It's a physical description and has absolutely nothing to do with the underlying protocol and technology, which can be anything from USB 1.0 up to USB 3.1 Gen. 2 combined with Thunderbolt 3. Thus, a USB-C machine without the benefits of USB-C, such as reversibility, is mechanically impossible to produce
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