All things being equal, your proposition is true. Any rodmaker will tell you this if they are being honest. This is actually where the no fault warranties came from in the first place. As rods became lighter and faster, tip sections began breaking just do to design implications under the same usage conditions. Many different rod mfgs and custom makers (who used to work for major mfgs) have told me this directly. The old IM6 and even first gen graphite blanks are the most durable. They are heavier, but they perform well and are rugged. This is why a lot of the instructional, beginner, and kids rods are made of this material even when introduced today. It isn't that the material is any cheaper. It actually is all about the same price. And the lighter rods generally use less material in the same linear amount of blank. It's actually a design feature meant to provide a benefit based on the intended use of that product.

With that being said, all things don't have to be equal. If you learn to keep less pressure out of the tip section of a fast action rod you will be far less likely to break it. If you learn to "baby" the tip section when handling the rods, you will be far less likely to break them. And if makers would package them better, they wouldn't get damaged in shipping. Sticking a tip in a tube and letting it bounce around during shipping is a good way to have high shrinkage costs as a mfg. or custom maker. But a lot of them do it!