LEDs is a great example for a current comparison, people were talking about diodes decades ago for lighting, but it isn't until the last few years that they hav

LEDs is a great example for a current comparison, people were talking about diodes decades ago for lighting, but it isn't until the last few years that they have reached cheap and efficient enough versions to really challenge the lighting marketplace, especially for growing plants. 10 years ago growing with diodes was expensive as hell for negligible returns over specialty growing bulbs. You buy LED tech released in the last year or two though and you are going to be throwing away or selling your old fixtures as a waste of electricity.