No, they don’t. Assets, as well as any other rights or resources, undergo value changes depending on several circumstances. Such circumstances may be related to the resource itself (internal) or else to its surroundings. Reductions in value suffered by assets are called depreciation.
Thus, for instance, exploitation rights for a mobile communications business won’t be worth the same if only one network is given the permission to work with the 4G network or else if more than 10 licenses have been granted to work on the 4G network. The more competitors are in it, the less worthy the resource becomes, as competition reduces its exploitaiton prices.
On the other hand, from an internal point of view, assets also depreciate “on their own”; for instance, they become less worthy as time goes by. Thus, a desktop computer with a Windows 98 operating system could be worth 10 times as much when it was launched into the market than it is worth now. This is due to time, to the wear and tear associated to use, and to the advances in technology that make it less worthy than it was before.
The same could be said regarding equipment in a factory, motor vehicles in a company, delivery vans or even intangible assets.