Why should I need an adapter for something that used to come standard?
The same reason you needed a new charging cable every time the USB standard changes: because technology standards change over time.
If anything, audio adapters have been a thing for decades longer than cell phones have existed. This is not a new development at all.
What about a micro-SD card?
My phone has an completely excessive 512GB of storage, and I can use USB drives (including micro SD adapters) if I really want to save something to external storage.