Most car purchases come with a 3year warrantee of some sort so other than wear and tear servicing costs are the main expense - for some time period anyway. So in some ways it comes down to purchase price. Leasing can just makes them a bit cheaper to buy on the never never. If the car doesn't finish up as it should at the end of a lease that can cost. Seems some do have that problem even just underestimating mileage.Thing is, I reckon in this scenario the old cliche is true. If you have to ask anything about the cost of purchase, maintenance etc, these cars probably aren't for you. Many of these owners, to an extent, probably couldn't care less if their <insert supercar brand here> isn't reliable in the traditional sense of the word. And if a replacement wiper costs £399, 'so what?' will be their attitude.
Supercars - driven as they are on say Top Gear they might fit more than one set of tyres while filming, I suppose high end traction control helps but the brake type used to avoid the cost of a limited slip diff are a bit different unless true traction control is added. A number of them can have problems with things like speed bumps. Some such as what Aston Martin did and maybe still do make are produced for normal use. Some others try that at times as well. Seeing Bentley mentioned. They were the Rolls for an owner that wants to drive themselves. I was tempted by a used Lambo once, Sort of why not as I could. Sat in it and adjusted the seat to suite my size - couldn't reach the gear lever. Made for F1 drivers who are usually small. These may still be about by various makes but gear change will be some where else now.
Parts costs vary according to make and price range. Odd fact is that all cars use similar things. There is a lot of money in spares. They've got you so if you want to keep the car running people have to buy. After market spares rather the OE can work out but can just be what would be expected for the price paid. Toyota made a lot of noise about this in the past. Not sure they do the same now - spares exactly the same spec as fitted on the car when it was new so they cost more than other makes.
Fact is cars are status symbols to some. How much status depends on how much they can afford. There are oddballs as well. Take BMW's. A popular fleet type buy because the residuals are very good when they are finally sold. That is down to desirability and reputation. Reputation - well just like all they can have problems and sometimes do - serious ones. Audi is a step down from those - a VW really as much of it as there can be. Merc's - interesting to look at what servicing means if some one want a very high mileage out of one. Popular with German taxi drivers and includes an engine rebuild.