Lord Beerus wrote:
When was it ever confirmed that Freeza's army were based in one galaxy? They were all over the universe. Hell, Beerus and Freeza met at one stage and even became acquainted. Plus, Kaioshin states in Super that there are currently 28 planets with life on them. Not that that there was always 28 planets with life on them, even during Freeza's unchallenged reign of terror, Majin Boo's lengthy rampage, Beerus doing his usual destroyer God shit and the Saiyans running amok for shits and giggles.
Plus, and as I've said before, Kaioshin had been following Babidi in his spaceship, with the sealed Majin Boo inside, across the universe for God knows how long. And considering that Kioashin was the last of his kind, and Majin Boo had destroyed so much of the universe when he was set free that original by Babidi, Kaioshin had to keep constant tabs on him, to make sure that the evil, ancient Djinn didn't come back to life. And as a result to protect the life that remained in the universe, he just didn't have the time to create new planets, as he was supposed to given his role as a creator of life. He didn't want to lose track of Majin Boo and give Babidi the chance to resurrect Majin Boo, even if that meant he wouldn't have the time tor create new life-being and planets. Especially since, on top of that, Babidi was recruiting minions to assist him in bringing Majin Boo back to life. Kaioshin ultimately had to make the decision to forgo creating new life that was destroyed by Majin Boo, Freeza, the Saiyans and Beerus to ensure that Majin Boo would never be released again and bring the universe to it's knees.
I will agree that 28 planets is very low number, but it's not entirely unreasonable. Considering how much destruction has come from so many different parties for several million years, the universe being quite barren with life should really come as no major surprise. Everyone from Kaioshin, to the Kais, to Beerus, to Freeza, to Majin Boo, to the Saiyans, are at major fault for this. And people wonder why Universe 7 has such a low mortal level. Their lack of attention to their own universe has gloriously come back to bite them in the ass.
Like I said, if Freeza's forces were all over the universe and not just in our galaxy, then their business would be even more ridiculous with only about 28 planets around in the whole universe.
In the same light: Freeza made a business with planets during his reign of terror. Shrinking the number of planets (i.e. possible customers or possible commodity) anywhere near that amount (28) would be insanely stupid.
Kaioshin specifically mentions Namek, Vegeta and even Sadal, which further implies that no tremendous amounts of planets have been lost recently.
In other words, we didn't lose like lose a number of planets several orders of magnitude above these 28. We are still within the same "tier", if you want so.
Also Majin Boo's rampage was millions of years ago. (Unless you are counting the anime filler material of Kid Boo destroying worlds.)
If that would be a reason for the "28-planets-tier" (give or take some destroyed ones), then this would make Freeza's business look very ridiculous again, since Freeza was actively in business in "modern age".
Or rather, what was there to conquer for Freeza and his father, if there were only that few inhabited planets to begin with?
And whom to sell them to?
I can totally agree that U7 is "lacking" a bit, because of these numerous factors that came into play.
But 28 is still even then just an unreasonably low amount of inhabited planets for a
whole universe.