Those mostly aren't "type-A devices". The connector is not the protocol. Except for those physically integrated into a type-A connector, those are mostly USB-2/3 devices that generally ship by default with a cable that includes a type-A connector at one end and a type-B or mini/micro-B at the other.

I too have an external audio interface, a printer, scanner, and external HDD, and they are all connected via USB cables that have a type-C connector at one end and the relevant B subtype at the other. These are now cheap and ubiquitous. My keyboard is lightning to USB-C, and my mouse is bluetooth. As for flash drives, I buy the double-ended ones these days.

The adapters I still use are for an older U2F dongle that is physically integrated into a type-A connector, which is due for retirement later this year, and a Thunderbolt display.

So the writing isn't just on the wall for USB Type-A connectors in my household, they're basically gone.

As for what happens to all the cables with type-A connectors that shipped by default, those are in my travel kit for device charging off wall-warts or vehicles that often still have type-A sockets.