What, you think they're gonna digitally alter all future airings of IAMD?
No. We just have to use our imagination.
Or we can start retconning.

Here we go... The U.S.S. Defiant from IAMD came from the TOS prime timeline into the the pseudo-mirror universe of the TOS prime timeline (pseudo-mirror universe, since its prime universe had already been slightly altered by the Temporal Cold War and the U.S.S. Enterprise-E's time travel in
First Contact). The U.S.S. Defiant from the Nero-altered
Star Trek XI timeline, however, looks exactly like this timeline's U.S.S. Enterprise (when it exists at all, that is), but was NOT the one that appeared in IAMD. It continued to exist in its timeline... or disappeared into the IAMD episode of what we might call, for simplicity's sake, the mirror Abramsverse, where it became the prototype for the re-engineered mirror U.S.S. Enterprise and its crew, which look exactly like the U.S.S. Enterprise and its crew from
Star Trek XI. Does this make any sense at all?