Yes I do read that now and Cain buildeth a city and his offspring be a mixture of professions from tent dwellers and cattle herders to the profession of musical instruments and also the creators of artificers of brass & iron. Point taken. There not seem to be much in the way of description with what professions the line of Seth did excel in. Only that we know they were just as intelligent in being able to build a ark the size of the titanic. As to Noah being the only faithful man upon the earth at the time. Well not quite . You had Noah’s wife and his their 3 sons and wives. But that was not the point I was trying to make. The point I’m trying to make is that God could have easily brought forth other generations of faithful believers from the gene pool of Noah and his sons families and also from the ungodly in their future generations that is of course if they were fully human. Why destroy a entire world if it were merely the sinful nature of humanity which actively continues on in the new world everyday which has continued for some 4-5 thousand years when in the old world it was destroyed midway between one and two thousand years. It seems to imply much darker implications than merely just humanities fallen nature.
Your statement about Noah’s family also being faithful is false three times God said in the bible only Noah was faithful like in one example in the verse below.
7:1
The Lord then said to Noah, “Go into the ark, you and your whole family, because I have found you righteous in this generation.
God destroyed the world with the flood because only Noah was faithful and didn’t conform.
If we want to know when and why God will destroy the world in the future we have to stop guessing and look to the only true source the bible and see when and why God destroyed the worst in the past.
God destroyed the world with the flood in the past because the faithful dwindled down to just one man Noah and God will destroy the world with fire in the future when the church conforms and stops growing and dwindles down the a faithful remnant like we see starting to happen today.
Revelation 20:7-9
7 When the thousand years are over, Satan will be released from his prison 8 and will go out to deceive the nations in the four corners of the earth—Gog and Magog—and to gather them for battle. In number they are like the sand on the seashore.9 They marched across the breadth of the earth and surrounded the camp of God’s people, the city he loves. But fire came down from heaven and devoured them.