Getting sued is expensive, stressful, and time consuming no matter how the case turns out.
If you sue all the commissioners every time they issue a decision that you don't like sooner or later they'll see your next request and think "Can I afford the inevitable lawsuit if I say No like I should?" and/or "Can I take the stress? Can my family?" So next time they'll give you what you want just to avoid that whole mess.
IANAL but it sounds like qualified immunity is intended to short-circuit this: even if you made a reasonable mistake here and there you can't be sued by some bullying jerk.
Standing: without a reason that looks remotely viable, a court might just throw it out without requiring a defence.
Risk: big companies have legal departments on hand to make your life hell for even trying.
Reward: smaller companies don’t have enough money to be worth your time to sue. Even if you’re trying to “send a message” the first attempt is so expensive for no gain, it’s not worth your while.
Government departments tend to fall into a bad middle ground. There’s enough money to be worth fighting over but they’re not always fantastically well equipped to defend it (or at least they’re perceived as such).