The big fish they were after were you and me. This was never about anything but padding the numbers to justify new and more restrictive anti-firearms laws. When their lies about firearms traces was found to be false, they needed to do something to make them more believable.
It was a criminal idea. It was a stupid idea. The scheme fell apart, as irrational schemes are wont to do.
Firing the current head of the BATFE and replacing him with a known anti-Second Amendment bigot
is most emphatically not
the needed result.