Genesis 6 is the days of Noah a specific generation of evil.
True. However, I don't believe this changes anything I said. Sin is progressive. It has always been progressive. It gets worse and worse over time. Which leads to apostasy and reprobation.
Which is the generation you're referencing and the generation that Paul referenced in Romans 1.
Rom 1:18 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness;
Rom 1:19 Because that which may be known of God is manifest in them; for God hath shewed it unto them.
Rom 1:20 For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:
Rom 1:21 Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.
Rom 1:22 Professing themselves to be wise, they became fools,
Rom 1:23 And changed the glory of the uncorruptible God into an image made like to corruptible man, and to birds, and fourfooted beasts, and creeping things.
Rom 1:24 Wherefore God also gave them up to uncleanness through the lusts of their own hearts, to dishonour their own bodies between themselves:
Rom 1:25 Who changed the truth of God into a lie, and worshipped and served the creature more than the Creator, who is blessed for ever. Amen.
Rom 1:26 For this cause God gave them up unto vile affections: for even their women did change the natural use into that which is against nature:
Jesus even spoke of how "from the beginning this was not so".
So there is a gap between the faithful righteousness of Adam, Eve, Abel and Seth to generations that gradually built to the reprobation of the generation of Noah.
The flesh of man that we experience now in our generation is dramatically more susceptible to suffering in the flesh than it were in the first generations of humanity.