There are people who own penthouses they've never seen. At some point practicality just goes out the window.
This isn't a matter of practicality but economics. The penthouse collectors don't need parking. A high rise with parking is practically screaming that it's a vanity project--the economics that demand a high rise don't work if you have to add dead space for cars. The math only balances if your building is entirely penthouses and valet space for sports cars.