Hello,
You are correct and incorrect. At the time you wrote the solution, the statement s were valid. There is something called UASP (Specific to USB 3.0 and higher) that has been around since 2011/2012. It was only in the latter part of 2015 that you began to see it incorporated in all sorts of USB enclosures and devices. It's even in a cheap $11 case I bought at a retail shop.
UASP is Universal Attached SCSI Protocol. It allows for better management of data transfer over USB for devices with frequent constant I/O. Some people may think I am referring to attaching a SCSI device to a USB. Not quite. SCSI is parallel and ancient but it had a superior method of handling data reads and writes with queue depth storage. It takes USB and adds SCSI protocol on top of it giving your USB device access to SCSI commands on the controller thus increasing performance, latency, throughput, while reducing CPU overhead.
Can your USB truly get 5Gbps ? Well, the answer is pretty much "With UASP it's common to see 4.8Gbps. In some situations you can event get 4.999999Gbps. In rare cases it can even surpass 5.0+ Gbps giving you near SATA 6 speeds". I thought it was tripe until I saw it with my own eyes. There are drawbacks with any technology. Technically TRIM is possible now because you can send those commands through to the device. I've been unable to get it to work but that is an OS issue.
Mac OS X 10.8 added this feature in the IOUSBMassStorage extension. Windows 8.1 and higher have it. Linux just added it.
The only question I can't answer is UASP with USB RAID devices. I hear mixed answers about this combination. So far the answer is, "They don't exist". Yet I have seen it advertised recently. I haven't been able to confirm if its true or false advertising. That's only with the any combination of USB 3.0 w/RAID or w/eSATA+RAID.