My usb 2.0 bus doesn't exist anymore

What exactly is your issue? Why would you need USB 2 ?

You do not say what exact MacbookAir this is.

Older macs those components all use USB2 bus, for the device tree, even the mid-2012MBP USB port is USB3 .

Newer Macs may well use a USB3 bus across the board, for the device tree, like bluetooth, camera, keyboard etc.

Your USB 3 port is backwards compatible.

USB2 and USB3 compatibility is not the issue—

There is something else a mis here.

Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379

When you say—don't show, what are you expecting to see where?

Finder >Preferences There are setting to show USB devices on the sidebar and the desktop

GhostIG Said:

"My usb 2.0 bus doesn't exist anymore: My usb 2.0 bus doesn't exist anymore somehow ..only my usb 3.0 bus remains ..how do I get the driver?"

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Backward Compatibility:

All these items: Have they worked on this Mac in the Past? If 2.0 items are not working, it is probably the device itself (not the Mac) that is not allowing these to be read. That would be because it is not compatible with USB 2.0.

Use a USB External-Powered Hub:

As for devices that no longer work.... Using multiple external devices through a songle hub can consume lots of power. So, use a hub that powers off of USB.

GhostIG Said:

“[...]I initially thought all ports were spoit until I noticed that my ports now only read usb 3.0 USB hubs that arent 3.0 dont work”

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Read the Original Packaging of the Hub:

Next time you go for a hub, be certain to look on the original packaging. Make sure it reads that its compatibility is for both 2.0 and 3.0 devices and works with your macOS (or iOS, if applicable). The hub’s compatibility, would most certainly overrule this interoperability.

Drivers? Probably, it’s Plug-and-Play:

I’m not so certain there would be drivers just for an external hub. But, contact the manufacturer and ask if such drivers exist. If so, get them from none other than the manufacturer. It is most likely Plug-and-Play: Plug in the hub, and it works right-off-the-bat, so to speak.

Back Up the Mac, if Installing Drivers:

Lastly, prior to driver installation, be sure to backup your Mac, with Time Machine Backup. That way, you will have something to restore your Mac from, should anything go wrong after the installation.

GhostIG wrote:

I need it because most of my hard drives come with usb 2.0

There is no issue running your USB2 enclosured drive on your macBook Air w/ USB 3.

They are compatible.

You are welcome!