Cool exists on a sliding scale.
The term sliding scale comes from economics. In some situations, a wage or fee structure is based on another factor – such as the cost-of-living index. The scale does not necessarily slide in proportion, but it moves with the predetermined factor.
When it comes to cool, the adjusting factor is the relative definition of cool which is made by whatever group is defining it. What is cool to gamers is probably not what is cool to hipsters. What is cool to someone who buys clothes from shops on Rodeo Drive is probably not the same as what is cool to those who shop at our local mall.
Cool changes depending on who you talk to and when you talk to them. It is often defined more by what is not cool than what is cool.