Other than storage, no peripherals care about USB 4. We can't get away from USB-A because all of the devices that MATTER use it and its variations. Even today no one that I've seen makes a USB-C to USB-Micro (or USB-Mini - yes, I still have multiple products that use that) cable. I have no interest in having to chain multiple adaptors off all my computers for everything I do. Keyboards, mice, printers, cameras, microphones, audio adapters, gaming controllers, smartwatches, sensors, Arduino boards -- none of these things need any more speed or any more power. They don't want a new connector and they don't want to pay royalty fees for use of a new connector. The only things that might benefit from USB 4 are monitors (and how often to people replace monitors anyway? I ran my U2410s for a decade and only replaced them because I wanted a higher refresh rate) and storage devices (and to be honest I don't use external storage that often since online storage is so simple these days).
Section 2.2 of the USB Type-C Specification[1] explicitly forbids this kind of adapter:
USB Type-C receptacle to USB legacy adapters are explicitly not defined or allowed. Such adapters would allow many invalid and potentially unsafe cable connections to be constructed by users.
