You sound come across as competent. If you don't feel justly compensated for this loss of credit, you need to walk.
We as a industry should improve our processes and not let some MBA guys screw engineers over. It is probably happening elsewhere too, especially the creative jobs (advertising etc).
They don't even mention all the ones I know about, like Planet Labs, or Blue Origin, or places like JPL.
What is your alternative here? Keep getting exploited and keep being frustrated? You need to consider yourself in, say, 20 years. Consider you decided to stay, how do you feel in 20 years? Consider you decided to try something else, how do you feel in 20 years now?