In the original relativity theory of Poincaré and Lorentz, when a
clock and meterstick moves from one inertial frame of reference to
another, the clock ticks at a new rate and the meterstick changes
length but these changes are undetectable. That's a covariant theory.
I interpret an absolute yet undetectable frame of reference to be
equivalent to an axiom of space incommensurability and time
incommensurability.

To assert the converse, that clock rates and meterstick lengths don't
change and that time dilation is a mere consequence of a change in
perspective, is Einstein's theory.

The answer to the question, "Is Einstein's special theory derivable
from the original relativity theory of Poincaré and Lorentz?" seems to
be yes. It only requires a little redefinition and makebelieve,
right?

Shubee
http://www.everythingimportant.org/relativity/special.pdf