That's exactly how >1Gbit/s connections get sold. Hardware with multiple high-speed ports is very expensive, so typically you have 1 2.5G/10G port LAN port and

That's exactly how >1Gbit/s connections get sold. Hardware with multiple high-speed ports is very expensive, so typically you have 1 2.5G/10G port LAN port and all the other ports are 1G. So they say you can have multiple concurrent 1Gbit/s streams.