It’s an accident of circumstance you even need to buy a yubikey - your iPhone, iPad, laptop, android whatever can do everything a yubikey does. There just needs to be enough demand and time for OS and hardware vendors to come around to shipping and integrating this stuff by default. Suddenly you’ll own 3 or 4 yubikey equivalents without buying any special auth devices.
25 years into the web and our login tools remain pretty barbaric. Maybe in 25 years we’ll have it sorted out. But change is coming. Call it 2fa, webauthn, whatever - regardless of the details username/password auth (on its own) is dead.