Double butt

I have done about 10 Arcade runs, on elite and lots of FSC runs on elite, and I got 0 orbs.

We'd need more detail, to be able to pin down how improbable your results are.

For example, let's ignore the Arcade part for a moment, because the orb chances depend on exactly which levels you've run. And let's say, for the sake of argument, that "lots of FSC runs" means 10 FSC runs. And let's say that the game is tuned so that you get 0.17 orbs per FSC run on average. (There is a huge amount of uncertainty in this figure.)

Then you expect to have gotten 1.7 orbs in your 10 FSC runs. According to the Poisson distribution with λ = 1.7, the probability of getting k = 0 orbs on those 10 runs is λ^k e^-λ / k! = 18%. So your FSC experience is not surprising. Sorry.

Even if you got something more like a 1% probability, I still wouldn't be convinced that anything was amiss, unless you also told me that you had decided to make this thread before ever doing your study. I mean, for every player who makes a thread like this, there are 100 players who didn't make such a thread, because they found orbs and didn't have anything to complain about. In other words, players will sometimes get unlucky with orbs, and sometimes you will be among those players, and sometimes you won't. This effect is called observational bias.

The good news is that by running FSC and the Arcade you have earned a bunch of crowns, which you can use to buy orbs outright.