That's because the roulette is fake. You actually have a given chance of a prize, then it picks the rest of the prizes that will appear near it, often including ones that your current tier of ticket cannot actually give. In fact, while it was previously thought to be randomly selected, after watching well over a thousand tickets I can confirm there are preset fake categories that will surround your real prize!
For example, a 4 star ticket can only win 10k, 30k, 500k, or 1M as a money prize. However, 2k, 5k, and 100k still appear around it, and 1M and 500k appear far more often than they can actually be won. But it doesn't end there, if you watch enough you can see patterns form. If the ticket shows 10k, 30k, 100k, 500k, and 1M, you are guaranteed to get 10k. Every time. If it shows 5k, 30k, 100k, 500k, and 1M, you are guaranteed to get 30k. Of course, that is only showing the lowest winnable prize when they're all cash. However...
While I don't remember the exact layouts now, you can see more patterns. If I remember correctly, one of them is 10k, 2 cars, a part, and an invitation. You are guaranteed to get the first of the two cars in that order.
500k and 1M prizes, as far as I can tell, are always the same layout. 2k, two fake prizes in between I forgot (car and part?), 500k, 1M? Guaranteed 500k. I wish I could remember these better, but unfortunately 500k is only a 4% chance, and 1M is only a 1% chance!
Anyway, the point is, Polyphony have deliberately chosen to tease you with better prizes. They selected the categories that surround your tiny prizes. They intentionally made sure that your 10k prize looks like it was just about to hit 1M, though the chance was never there, it was never going to stop on 1M.
At this point, I know when I'm going to get a decent prize just because the layout is unusual. I don't see 1M often, so when it does come up, that pre-determined layout isn't familiar to me, meaning I'm going to get that 1M. Otherwise, I recognize it as one of the pre-determined layouts that pop up all the time.