Why was Colonel John Wilder ONLY a colonel?

You have to understand military ranks or have been in the military to understand my post. I know that the space agency depicted in THE MARTIAN CHRONICLES was not military but NASA-type. Still, they were using military style ranks, organization, and customs.

My question is that given the tremendous responsibilities Colonel John Wilder carried, that is, the entire, NATO-sponsored Mars exploration program, why was he only a full colonel and not a general? In other countries, a man with John Wilder's huge responsibilities would have been anywhere from a one-star to a three-star general. And one-star general (typically, brigadier general) would have been on the low side. Even in today's USA, such huge program directors are two to three-star generals.

Later on, Colonel John Wilder becomes the de facto governor general of Mars, even though he doesn't have the title. He's still the, 'Mars Program Director'. And he's still a full colonel! At least he should have been rewarded with the rank of brigadier general for his accomplishments. Typically in real life, a man like John Wilder would have risen quickly in rank. He should have been a two-star general. As a governor general he should have had the rank of lieutenant general (three stars). In comparison, the U.S. Army governor-general of occupied Okinawa at the end of World War II was a three-star general. Okinawa is an island in the Ryukyus, 350 miles south of Japan, and is only 80 miles long and 8 to 19 miles wide.

Let's just say, Colonel John Wilder got the shaft when it came to awarding him the appropriate rank he deserved. Perhaps the writer, Ray Bradbury, didn't understand military ranks.