I have no idea what fraction of the USB-C cables are certified, but they're not broken. They have the wires because people want the wires. For such a basic feature, this is more effective than certification.
However, I believe this prevents negotiation for power delivery. Even if not, you need the CEC pins for the cable to function and that is a data channel as well (there are firmware update specs over CEC)
This is not true at all.
I've bought lightning cables at the dollar store that are single-sided (one side has "UPSIDE" written on it, you can't flip it over), power only
edit: I buy a lot of cheap USB gadgets (fans, flashlights etc) so I checked my cables. Not one of my USB-C to C cables are missing data. Plenty of USB-A to C cables are, though. So as long as you avoid USB-A you may be fine.
in practice there are lots of usb-c cables that don't do data, which all lightning cables do. they're just not officially certified ones. which means they're not "real" usb-c cables.
again, the problem is it turns out in practice virtually nobody is using "real" usb-c cables, and if you want to stand on the formal definition, then we can formally say the standard has no real market penetration and can reasonably be disregarded until it catches traction.
if you can walk into a bodega and be assured that the lightning cable sitting on the shelf is going to be a certified and approved cable with data transfer, and the usb-c cable probably won't, then that's kinda all that really matters.
(and thus, we can see why certification programs like lightning exist. the $2 lightning cable on the bodega counter probably has better capabilities than the $5 usb-c cable on the counter because of the certification process.)