You're right. Thinking it over I'd omit the word "necessary". I rushed to generalise filters that, on reflection, are mostly apropos physical consumer products

You're right. Thinking it over I'd omit the word "necessary". I rushed to generalise filters that, on reflection, are mostly apropos physical consumer products. Some truly awful ideas just leapfrog the entire filter chain due to extraordinary luck or the power of relentless marketing money. That's the essence of pop music I guess.