That would be plausible, except the Solow/Justman book, which (mostly) tries to debunk the Roddenberry mythology, also asserts that it was unheard of for a network to turn down one pilot but order a second one.
I believe the difference between Star Trek
and these other shows being discussed (and correct me if I am wrong) is that the other shows were bought after the first pilot, and then re-tooled for the series proper. Star Trek
underwent the same process (the additions of McCoy, Uhura, and Rand; the change of job for Sulu; new costumes; etc.), but only after the second pilot was accepted.