TRLs got great press because a number of companies had to use them to report progress and needed to achieve various TRL levels to receive payment. So TRLs hit the ground running. NASA and other agencies loved them. The test of TRLs would be if they moved outside that sphere.
Many global defense companies, GE, Rolls-Royce, United Technologies, Boeing, and others have a good chunk of their business outside that sphere. Quickly after the technique was adopted it spread to the commercial side of the business. It was subsequently applied to company supply chains, and so rolled out. In the course of my travels, I caught wind of it at Tata in India, Bombardier in Canada, Embraer in Brazil, and the prestigious ITRI in Taiwan—all within a few years.