Additionally, the term Yubikey isn't likely to become synonymous with 2FA in any case. Most people don't know that yubikeys work in several different, independent modes, such as FIDO/U2F 2FA, or CCID smartcard, or Yubico OTP (those long annoying strings your yubikey types when it brushes your thigh or hand).
The CCID smartcard mode requires a pin, which is technically two factor authentication (knowledge of PIN and possession of yubikey), which is an entirely different thing than FIDO/U2F 2FA (which is what most people mean when they talk about using a yubikey for 2FA, not that "yubikey" and "2FA" are interchangeable terms).
This is further complicated by the fact that CCID smartcard mode can be used for ssh (via gpg-agent, with ssh keys inside the yubikey itself), AND, separately, OpenSSH (with other keys) can use a yubikey for U2F.
Using Yubikey to mean U2F is like people saying "Google this term", "the image is Photoshopped", "Hoover the floor", "grab me a Kleenex", or even "take the escalator". It possible "Yubikey" could become a generic trademark, but if possible people should be wary of using brand names in this way before it 'sticks'.