IDK, I feel like the majority of college players dont play in the SEC since there are more non SEC college programs than SEC ones. Since that was one of Seattle's points in the discussion I think that the statement quoted is incorrect.
Bad spacing and playing difficult competition is not something that only applies to the SEC. And more or less doesn't change the larger point that it is harder to do these things in the NBA. I don't think there is an inflection point or very specific set of conditions needs to be met in order to make this explanation valid. What it comes down to is it is easier in the NBA or is it not?
The SEC is hard, but the NBA is even more difficult.