The diagram is not "fake". It is clearly plotted using the Speeds as set by Boeing input into a typical Flight Envelope. You can make your own if you know the speeds.
Here is another V-G to help you understand how a Flight envelope is constructed.
What weight and altitude is the Vg diagram for?
It was explained to you in the post above yours. Weights as outlined in the TCDS and good up to 18,000 feet. Above that the V-G moves to the left.