I've shared before that TH and I fundamentally disagree on the way to communicate. I think what they're trying to say is that PCIe is being tunneled through the USB stack. I believe they're both packet-based protocols so on the first few layers that doesn't seem so bad. I'm sure whatever they've done is very impressive and kudos to the tech team.

However, maybe just buy computers that fit your needs? There's nothing I can think of about x86 that lends itself to a specific interface. ARM and RV have PCIe already. So, this just be an Apple specific thing I'm too non-Apple to understand.