Thank youbPCI-SIG but you can keep it to yourself and the datacebter market! Because ain't no one have money for that!
PCI-E 5.0 boards are already too expensive, and GPUs are still far from saturating PCI-E 4.0, faster SSDs would benefit consumers in absolutely nothing besides additional cost for the SSD and yet more additional cost for a full 6 Heat-pipe cooling solution for each of them or watercooling.
Faster networking would just benefit consumers in absolutely nothing.
So why bother? I think manufacturers do want to sell products and a motherboars with PCI-E 6.0 or 7.0 just won't.