What is the thumb rule in IT Job market?

Simple one decade technologies will help less in getting more salary, and will have less demand why because there would be some one in the market at any time to supply the demand for companies, So companies least bother about in finding resources.

But when comes to new technology less resources will be there in the companies and companies need to catch the technology advantage so demand raises but resource are less. salaries raises, job openings also raises.

if we apply same law inversely we can find the solution for IT Job market.

what is it : Find which are next decade technologies and learn them and be always in the IT cream resources list