If I were to guess, it's because the randomness of the upgrades is just a little too random at first. Once you get used to it, and get some upgrades, the game is no longer as frustrating.
After I beat the game, I installed some mods that made it so you were more likely to get certain gods (and you could choose which ones), and it became quite a bit more fun. Getting the combo powers, and ones that you were interested in, wasn't some super rare occurrence anymore.