I think there’s a couple pieces of the equation that are missing here.
First off, are you familiar with the difference between battery and motor current?
(I suspect they’re getting the 140a number from motor current which will not draw 140a from the battery)
This thread has some good info especially near the beginning.
But the gist of it is for motors:
Voltage in=RPM out
Current in=torque out
Your speed controller is capable of “converting unnecessary voltage to current”
If your board is geared for 50mph and you have a 50v battery (simplified numbers)
Your ESC will accept 50v but will only need to output 50v when riding at or near 50mph
Your ESC can accept 100a at 50v and output 25v at 200a which will increase your motor torque while under top speed. (More simplified numbers)
This is correct, however this is rated under the assumption these cells are charged to full, and used at 9.8a until they’re dead. While I can’t recommend drawing more than @Battery_Mooch ratings per cell. It is worth keeping in mind that we will likely do less damage with 3-10 second bursts of drawing 10+a than we would do at 9.8a for sustained periods of time.
More worthwhile reading: