I blame this tendency to overabstract on the emphasis on top-down design / teaching methods. Beginners are taught to abstract whenever possible, and aren't taught when to stop. They don't see the reason behind it, and instead add abstractions dogmatically, dramatically increasing complexity in the process. When abstraction is used well it definitely decreases effort and increases flexibility, but all too often it's overused and results in "object-oriented obfuscation" instead.