Given it's a game, and a piece of software, and we aren't there yet, it's not random, as there is no such thing as true randomness in game (software) development. The randomness is based on a time stamp, and if enough info is present a hacker can guess what the random number would be, but i side-quested quite a bit.
In this and many many other games each item on the wheel has a "player wins this" value, that represents how often the wheel stops there, the higher the value, the more stops a player gets. Since I've never played the wheel myself and don't know what items are good and not I'll try to explain it with other examples.
In 8-ball-pool you get a "roulette" kind of thing once every 24h, with coin prices varying from 15 (or something) to like 500 000. The game developer has set the "player wins this" value to the 15 coins price to be like 95% and the "player wins this" of the 500 000 to be 0.0001% or something. This means that in 95% of the spins the player would win 15 coins, and only once every 10 000 spins you would get 500 000.
Much in the same way, you would only get crappy candy-crush awards on most of the spins, and really only once you MIGHT get jackpot, or whatever the best price is.
Shortly this is done by the developers to encourage players to comeback every day and spin the wheel and potentially play the game, yet (the developer) not lose money, by giving away great things (like 100s of dollars worth of in-game items)
Edit: if the developer has some decency the "player wins this" number wouldn't be zero, and the spinner would still be based on the semi-randomness programming offers, so even though the number is quite small, there is still chance to hit it.
Source: game development theory during my studies of Computer Science