[knorker]

Aside from how the patent office no longer checks for prior art, but lets court fight it out, there's also the fact that technically these are not duplicates of prior art.

Technically using a laser pointer to exercise a cat is a new invention. Technically after that exercising a dog is another invention.

But even when not as obvious as that, imagine that you file a patent for the phone, and immediately someone patents every "step two", like the phone exchange, the ring, etc, to the point where you can't actually use your invention without licensing the next step.

That's one reason patent applications can be vague. It's not that they are not going to do the next step, is that they are patenting step 1 now, and are "inventing" step two right after.