There might or might not have been foresight regarding USB2.0 and its signal integrity requirements.
High speed digital signals are effectively HF to UHF signals, with all the problems they bring.
Generic Sub-D or DIN connectors are NOT designed to be viable VHF/UHF connectors. Certain EXACT models of Sub-D parts might be viable (as in, you have the part number and data sheet and have measured and tested that exact part).
A DIN or Sub-D connector will be electrically suboptimal already for a 12Mbps signal (though they have been used for protocols in that speed range, eg AUI for ethernet transceivers). Using it for a 400Mbps signal with a requirement of 500ps risetime could be considered ludicrous - if you ever toyed with experimental setups dealing with digital signals with even sub-10ns risetimes you will find that every inch of undisciplined wire or connector pin (as in, it is not part of a coax, or near a groundplane, or part of a twisted pair line) has a good chance of introducing gremlins into your system - or turning something innocent into an antenna.
Granted, VGA uses a sub-D connector for (analog) high speed signals that can be in VHF range - and problems (signal degradation, ghosting....) are not that uncommon, even though there has been ample time for manufacturers to optimize HD15 connectors (which are probably mainly VGA use today) for their most common usage. Some professional computer systems (SGI or IBM workstations ...) chose to use BNC connections or 3W3/13W3 connectors (a sub-D with coaxial inserts) for a reason for their analog monitor connections.
So, USB2.0 would likely have been impossible to keep physically compatible - and at the same time reliable - if a legacy connector like that would have been used.