I just reviewed a lot of numbers and came to the conclusion that most of us will not obtain all of the wheelspin exclusive cars through wheelspins. It requires a really obscene amount of playtime unless you farm wheelspins as a job.
TLDR -- between 4000 and 10000 wheelspins (counting super spins as 3) to get one of each exclusive car (5% likely to 95% likely).
The math:
At the moment, there are 46 cars listed as wheelspin exclusives. How many spins do I need before I get at least one of each car? This is the "coupon collector's problem," and it has a defined solution. The average (mean) number of spins before I have collected each car is 203. If you're the luckiest person in the universe (truly), it may be under 50 spins. If you're the exact opposite, you may spin the wheel 100 times a minute until The Elder Scrolls 10 is released and still be missing a car or two. For the rest of us, about a 50% chance you'll be done after about 200 spins, and 95% chance after about 300 spins.
But wait! Not every spin gives an exclusive car! Reviewing the numbers from this post by u/EchoLimaTango shows that wheelspin-exclusive cars are the reward about 3% of the time (pretty close to what I have found in a measly 285 spins, counting super wheelspins as 3). You need to spin that wheel about 6700 times to reach the 200ish samples of the 46 cars to be just 50% sure you caught 'em all (you'll get plenty of duplicates, though) Woo-hoo! The target is in sight! If I get to spin a couple of times an hour (including those super wheelspins), I probably will be done in a little more than 3000 hours of game play!! It might take as many as 5000 hours, or more if my luck is shit! If you're really lucky, only 2000 hours (about 4000 spins to be 5% sure of getting each car once)
Note, these calculations make the assumption that each wheelspin-exclusive car has the same odds of dropping. Probably not the actual case.
Also note that I let the Chrome AI help me out with the calculations, since I'm old, tired, and no longer interested in doing stats on paper. AI did not write the text here. Also since I'm old and tired, I'm going to bed now. 😄 😴
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Edit to add:
Some commentors seem to think I'm ranting about the game or making an unfair criticism given their own experiences in collecting cars. Not true. I absolutely love this game. The map and imagery are gorgeous (so much dopamine from just driving around and looking!), and the regular game play is outstanding. I also enjoy discovering the underlying mechanics of the games I play, and learning how the wheel spins work is fairly straightforward. However, now that I've done the math, I find it remarkable just how long the odds are when we're talking about wheelspin-exclusive cars.
If you want to get some more insight into how the wheelspin mechanic works, read about gacha games. The wheelspins fit the concept to a tee; I find it strange to have that sort of mechanic in a game that isn't "freemium." I know the wheelspins have been around for at least 4 FH games, but the current probabilities have pushed things toward the unpleasant side of gacha.