And DMs who drop/lose players can also find new ones. But also may not, just as players may not be able to find a new DM (generally rarer than players).
Frankly, I don't really see either as being more 'powerful'. Both sides can survive losing the other...and both can end up not gaming again for a long time if the same thing happens. DMs have control over the rules and running of the game/setting, but it's generally a good idea to at least be listening to any problems brought up by the players. But players shouldn't be trying to dictate how the game is run, as DMs tend to react poorly; most have a certain idea of how they want things to go, be it in the plot, style, or whatever.
It's a balance, really, and the most fun to be had likely comes about through a compromise of what the players want, and what the DM wants. Go too far to either side, and someone is more likely to be disappointed. And if either side tries to exert excessive influence over the other, a broken-up group may be the least of everyone's problems.