Sparkie was a use case of 1, and we were all impressed & hopeful based on that example. I don't remember seeing any other reports here where the owner has high mileage on the car (150k+) with no issues. However there are multiple reports on the forum of battery sections or packs having to be be replaced either inside or outside of warranty. You are correct that we don't have all the data, and can only base conclusions from the owners posting here. It would be great if GM made the actual battery data public, however that's unlikely to happen, so we just have the owners experiences to go on.I do think it's unfair to lambast all Volts because of your experience. There's a guy named Sparkie that drove his Volt almost to 500k miles... is that typical? Or is your experience typical? Hard to say without real data instead of anecdotes, but it does seem that Volts can go a lot of miles w/o needing a new pack, you just got unlucky, which again can happen with any car. Though it does seem to be true that "getting unlucky" in a Volt is more expensive than in similarly priced cars.
Having put a lot miles on various cars, you do have to deal with some things as the numbers creep up, such as brakes, suspension, wheel bearings, water pumps, and ignition system. However I've never had a $10k repair on any vehicle. I don't think I've ever even had an individual $2k repair outside of accidents. If you're diligent about maintenance and not abusive, they tend to be reliable for a very long time.