Yes, it's true. PCs, Servers, Laptops and Workstations are all designed to meet their expected usage, and the components are selected for them based on tolerances/quality which suits their usage.
In the case of a laptop, it's designed for power efficiency, which implies it's performance is likely to be compromised to conserve power. Home laptops are designed for a few hours use a day, and the assumption is that the lid will always be open (because consumer laptops generally do not interface with docking stations) and business-grade laptops are designed for usage around 10 hours a day, and allow for usage while the lid is closed.
Laptop hard drives are particularly prone to early failures, although whether this is due to being moved while in use, or overheating/overuse is debatable.
Long story short, I wouldn't be surprised if the laptop fails quite quickly if you leave it at 100% load with the lid closed.