"Even our most durable polymers would break down in much less than 65 million years and erosion and the action of plate tectonics would likely wipe out any trace of such a civilization."
If there are traces of dinosaur bones, feathers, teeth, etc, then there would definately be signs of dino laptops, coffee mugs, or whatever else they built. Sure, the polymers would have broken down, but some would have fossilized or left some traces of their existance.
We also have the donosaurs to thank. Without them and their era's vegatation, we wouldn't have all the coal and oil energy to be as technological as we are. Imagine where the human race would be now if there was no coal or oil available. We will still be burning wood or maybe slowly developing hydro power. Plastics come from that petrolium also. It would be hard to make all those iPhones without plastic.