@vvasu001 i think what
@Richman meant is, there are steps that need to be taken in science to progress, like you cant get from a to z instantly..
so..you cant have a bullet train if your electricity is bad, and the arrival of new tech always make the old tech obsolete, like the invention of cars lead to horses and carriage functions demoted to just sports and recreational..
btw, dr. stone manga explained this very well
though..it could be easily explained
we got the other way around..we do get a period when cowboys raiding trains on a horseback. cars and roads made horses and carriages obsolete..not trains
weapons will always be weapons no matter what type you have..our policemen got a revolver and a baton when a drone could take a heavy guarded convoy down
i dont get the relations of lamp and scalpel tho..it's different science so both still and should exist
hope that answers some of your worries..now let's enjoy these fluff chapters (fff..how many chapters are these fluffs?)