You can’t win them all.
They are geared for all levels of play.
Lower levels have some they can win, they don’t give out lots of DNA because lower level players don’t need lots of DNA.
Higher level players can win more challenging incubators that the lower players can’t, because they need very high numbers of DNA for each fuse of the higher creatures. These higher level/more challenging incubators have much more DNA in them.
If lower level players were awarded vast amounts of DNA, they wouldn’t have the time and experience needed to play intelligently at the higher arenas.
That’s just my opinion.
I see cheaters with high level accounts that haven’t a clue what they are doing. They got there quickly and didn’t take the time to learn the game.
No need to buy anything in this game, you’ll get the good stuff eventually if you play.
TBH, buying incubators is rarely worth it.