Agreed but not many laptop users will know this or have the knowledge to strip the laptop down to clean out the collection of dust and debris, it would probably help if the manufacturers and the computer shops advised the buyer to take the laptop in for a service and clean every twelve to eighteen months but they won't as this would potentially extend the working life of the laptops and therefore reduce the sales of new laptops.
I always advise people to use their laptops on a hard surface ie; an upturned tray or worktop to allow free circulation of air through the cooling system of the laptop, using a laptop on soft furnishings or on the floor will shorten the life of the unit quite dramatically.