It's a moving target. If a sunset clause is something that could be used to recognize when new technology is available....
I'll use the example of grain drying. The burning of straw to dry grain sounds like a practical solution, but in a lot of western Canada, for instance, where a lot of the grain drying is done, we don't bale straw. I've never had a baler on my farm. You'd be looking at buying new equipment and putting up straw in a dry year, hopefully, to have it sitting there for a potentially wet year the next year, or two or three years down the road, when you use your grain dryer.
It just isn't a practical solution, and that's an example. As technology improves, there will be other things that come. Maybe we'll all be using pellets some day to dry our grain, but that technology doesn't exist right now and the infrastructure isn't there for it.