I'm sorry but them saying pruning already exists does not make this idea silly, and I've already responded why. If you have a reason why my response to that was inadequate then I am all ears.
If you mean any Bitcoin devs then I'm sorry - none of them have (or likely will) respond to this topic.
Please go and actually find out about the pruning that Bitcoin uses already before proposing something inferior to replace it with.
Try and understand that naive (and sometimes just plain stupid) ideas to "improve Bitcoin" are suggested every day on this forum by people with no software development skills whatsoever (and you have failed to show that you have any).
If the developers were to waste their time having to read and respond to every suggestion such as yours then they would never have time to actually do the work that they are doing (which is why you are not going to get a response from them).
So again - if you really have anything serious to offer then firstly go and study how Bitcoin pruning works before trying to tell others how "it should work" (when you've not even displayed that you can code).