For the most part they don't need colors because all of the ports are the same. One recent exception was that the 2016/2017 MBPs had inconsistent Thunderbolt bandwidth because they didn't have enough PCIe lanes. IIRC left side had full 40Gbps ports but the right side had 20Gbps. The 2018 version has full speed on all four.
EDIT - another potential point of confusion, they don't mark Thunderbolt ports vs USB-C ports. On any given device they're all the same, but they expect you to know that the 12"-mini-macbook is just USB-C while the Pro and Air are all Thunderbolt.
So yeah, it'd be helpful to have some symbols on the laptops. They do label ports on their desktops. I assume this comes down to Ive not wanting labels on his beautiful chunk of aluminum where someone might accidentally see them while using it.
It'd be harder to do markings like this on USB-C ports though. They don't have a big visible chunk of plastic in the middle.
Beyond just switching to brand + version number (ie [USB logo] 4, [thunderbolt logo] 3, etc.), I don't know of a great way to really go about this. Otherwise you end up with the super speed championship edition thing you posted, which isn't going to help anyone really.
I think the color one was a great idea on their part in that you didn't have to look too close to see which port you were plugging into, but all it takes is one detractor to deviate from it (say if MSI came out with a gaming laptop with red USB2 ports), and then the whole idea is shot.