Good abstractions allow themselves to get out of the way when necessary. There are for sure bad examples of abstractions, but there's also plenty of ORMs that l

Good abstractions allow themselves to get out of the way when necessary. There are for sure bad examples of abstractions, but there's also plenty of ORMs that let you bypass the abstraction completely when needed (or use the parts of it still applicable). I also don't really understand your last statement. Abstractions, pretty much by definition, never allow you to do more than the underlying technology they're abstracting. They necessarily limit power in order to make code more comprehensible and maintainable. That's true for any abstraction I can think of, leaky or not.