I totally love ur insight on this!,also me at first thinking how would author construct the time machine basing on reality when senku proclaimed he Will be making it.The essence of this manga to be based on reality does still stick until the end,not mentioning the parasitic machine still be possible created/will happen IN!THE!FUTURE!
(You guys must have guessed that we are on stage where AI itself does have it's own mind,example would be the elon musk's invention of robots who could help humanity from labour to enhancing the knowledge of us advancing in futurustic invention and stuffs)which kinda be scary in my opinion because we know one day we will "reap what we sow"
But but but! As senku's journey on retrieving humanity itself was like an eye opener for us that all the teachings and wonders we gather over decades will be hella useful when some catastrophic events will happen someday
Just for example the Covid-19 which nearly take over the world buuuttt instead!,not just scientist but the whole world figured the way out on this plague and alas! The current situation was the fruit we worjed hard to bear
Yet we knew there would still be countless calamity/catastrophic events or even destructive machine that we humans invents that could lead us in danger since we cannot avoid itself from advancing to technology,but Science might be the answer always(๑•ㅂ•)و✧
Although i don't like science that much,ever since humanity created a lot more easier/fun way to understand science,we better take it as a chance that maybe one day knowledge will solve everything (▰˘◡˘▰)
I love the plot and the wittiness of the characters. Even the medusa revelation was good and there are no tragic deaths, just fights turning into friends.
But honestly, people complain because they didnt get to see the time machine being done. I think people dont understand how difficult it was to the author to search for ways to understand how things are made up, like those rubber tires, spaceship and others. Even if the creation of the things used in that world are not that very detailed, it was possible to be created using 21st century science.
However, time machines are a bit hard, the author cannot just simply make their own details on building a time machine because scientist of today dont even have one. If the author continue prolonging the story with making a time machine, then it will just be a delusional creation in reality. It is nearly impossible since the author dont have a proper information for time machine making of the sort.
So I guess ending it there was pretty nice for the author!