Modern motherboards have increasingly been short on USB headers. For example a rear bracket with 4 USB ports has been available for years.
Today however the bracket has largely given way to USB cards which are actually less expensive.
Most recently USB 3.0 PCIe cards have largely replaced the older USB 2.0 PCI cards. Still there are some recent motherboards with old style PCI slots to support existing hardware.
Today with the proliferation of USB 2.0 hardware such as The HX1000i PSU and the WiFi card the demand for USB exceeds the available ports. Front panel USB ports want in on the headers as well as flash card readers.
Fortunately there are mass produced components to deal with the problem. Low cost USB 2.0 hubs are ideal for cable management. Extension cables are also available to easily place hubs on the motherboard tray.
The top USB hub has the undesirable feature of being vertically mounted while the lower USB hub is 90° angled. The angled design can be placed on the back of the motherboard tray easily with lots of clearance where cable management is dramatically easier.
Double sided tape can conveniently attach the hub to the motherboard tray. USB 2.0 can be 5 hubs deep without problem. If several spitters are needed they should be branched out. Extension cables are widely available.
The Fenvi AX200 PCIe card needs USB 2.0 to support the Bluetooth 5.0 function.
Wireless cards do not have access to the USB 2.0 that a motherboard mounted AX200 card would have available.
While a PCIe USB controller is not expensive the cost is more than designers want to endure for a WiFi adapter. The cost of antennas in the package adds to the cost but they are necessary as few have an external antenna unit.
Front panel USB 2.0 boxes now have as many as 7 ports but only one USB cable. This is due to the presence of a USB splitter in the box. The splitter chips are very low cost. Most old USB 2.0 class front panel headers do not have a USB splitter so they have 2 cables.