Sorry old farts, Greta will have nothing to do with the obsolescence of your class A amps. Guys like Roberto Guerra, Bruno Putzeys and Merrill Wettasinghe are the ones you should be watching. They are designing amps that sound as good, operate much cooler and cost sometimes cheaper. It’s only a matter of time before class A joins the group of nostalgic products that are relegated to museums as I am sure your sons and daughters will not want anything to do with your class A amps in their modern homes. So to answer your question, give or take 10 years. Yes, vinyl will outlast them.