Could Monitor Mode be built into Kali?

Currently I am going through the teidoius task of tracking down a good adapter to use with Kali. I am a newb. But I have been wondering if it would be possible to write a program to go beyond chipset limitations of pre-existing adapters. From what I understand Monitor Mode is a passive mode of tracking data without being able to read said data. Shouldn't all adapters be able to receive this data? While injection is giving data back to the system based on previous data? Please explain why this is impossible or why it's not been done yet. Thanks.

Monitor mode is always available via the ifconfig and iwconfig commands, like so...

ifconfig <interface> down
iwconfig <interface> mode monitor
ifconfig <interface> up

The airmon-ng tool in the aircrack-ng suite has a shortcut of airmon-ng start <interface>

I'm no chipset expert, but as I understand it, some manufacturers deliberately cripple their chipsets to stop monitor mode & packet injection. In terms of finding a good wi-fi adapter, there are several threads on it in the forums, as well as on forum.aircrack-ng.org

Monitor mode is one of the seven modes that 802.11 wireless cards can operate in: Master (acting as an access point), Managed (client, also known as station), Ad hoc, Mesh, Repeater, Promiscuous, and Monitor mode.

Wireless adapter has its own ROM and every ROM has a firmware which gives functionality to the wifi adapter.

Now this firmware is proprietary so it depends whether the manufacturer has implemented all the 7 modes of 802.11 wireless cards. If the manufacturer doesn't write code for monitor mode in the firmware then that chipset becomes hardware incompatible with monitor mode and packet injection.

If the support for monitor mode is written in the firmware then the chipset is compatible with monitor mode and packet injection but that's not it. To communicate with the wifi adapter you need to have a right driver which acts as an interface between kernel and hardware.

If there is no code written for monitor mode while building the driver, then you can't ask your wifi adapter to go into monitor mode even if your wifi adapter has provided with built-in functionality for both monitor mode and packet injection by the manufacturer. It just simply won't listen to you.

Thanks to open source community and contributors who build and distribute their own custom made drivers that help you to use all the functionalities of your wifi adapter.

To answer your question, you can't build a standard code for kernel which can enable monitor mode for all wifi adapters. You only can build a specific driver which you can import to kali and will be loaded by the kernel at boot time. Even the drivers have to be different for different chipsets. The only requirement is that your wifi adapter must support monitor mode by design.

Thanks for the helpful explanation, _defalt.