That still ends up with a lot of copylefted code ending up losing the copyleft protection. E.g. someone could build their proprietary product on top of a two ye

That still ends up with a lot of copylefted code ending up losing the copyleft protection. E.g. someone could build their proprietary product on top of a two year old Linux kernel, and not have to adhere to the GPL. > In some ways this is actually an improvement over the status quo. It solves the problem where software can't be relicensed because no one can track down all the authors. I wouldn't really call that an improvement. There's no longer even a point in relicensing code, given that the license only matters for code less than two years old.