I'll give you that in 95% of the weeks in a given year in D.IV and D.V having good game shape is a must. However, i can also say that it is not 100% equally important across all levels.
The best game shape against people that dont realize it's importance is a game shape that allows you to win, and thats not always a 9. When you drop from a 30k salary (which is good for a 20000 ranked in the world team) to a 2k salary, it doesn't matter if they're both game shape 9 or game shape 7. Every minute that the 2k salary is out there he's toasted.