"always". What is this always scenario look like if MS decides to drop the "must allow legacy boot / disabling SB / enrolling key" requirement and only enroll theirs?
Not saying that will happen, I honestly don't think Microsoft cares that much (my own opinion, speculation based on Linux's market share despite my own love of it).
Just... "always" is a strong word. People used that word when talking about secure bootloaders on devices like Droid2, etc. Things that were ultimately only circumvented by kexec. Something that would be much different in a SecureBoot scenario.