That's a good point. I may sound like a conspiracy theorist here but these views go back years ago and are based on some good old honest objective data so bear with me.
And BTW I love Cobb and Mountune for the support they've given our cars. I have their stuff on my car. But they are out to make money, period.
Cobb or whomever is out to sell a product. Therefore, they create tiered "stages" so that you and I think that if we buy X package we get Y power. A tune can be calibrated any way the tuner wants. It's interesting to me that in all those power gains that Cobb provided they still created tunes that scorched the tires in 1st and 2nd gear. They added all that power but it wasn't usable. Most every review I've seen of the Cobb staged packages has the reviewer in a state of ecstasy over how "1st and 2nd gear are useless". To me, that shows a lack of balance. Most of the power gains on a stock turbo - 90% I daresay - are in the tune. Even without an upgraded intercooler one can tune in the same numbers as a car with an upgraded one - the difference will be how long it can maintain power because of whichever intercooler. Either car can make the same power when relatively cold on a dyno - only the one with an upgraded FMIC will make it longer and more consistently. Back to the tune - a tuner can make the car do whatever he wants. He can limit the PSI or he can blow up the turbo on purpose, it's all in the tune. The Cobb tunes are what created those beautiful lines you refer to. They they give people like Matt Farah their products, free and installed free, he gets a zillion views and they make tons of money for his review. It's capitalism at it's finest, and many of us fell for it. On that note, who cares - I wanted a bigger FMIC and exhaust because it's fun and sounds great and I love installing. Plus I was considering turbo upgrade so I wanted the right hardware in place for that.
Anyhow, I suggest that the curves you refer to are created intentionally to sell a product. Put them next to a custom tuned car with zero hardware upgrades and you'll be surprised that the custom tune has the same numbers safely without hardware. All of this info BTW is buried in various threads on this forum, I can't dig it up right now but it's there. Most of the old school folks from 2014-2015 are gone now but they are the ones that discovered all of this a few years ago.
Personal proof, Mountune claims their CBE adds power to my car. I didn't think it would, but wanted sound. I installed it, had my tuner look at logs, and no surprise no tune upgrade was needed. There was no power to be gained, period, on the stock turbo setup with this hardware upgrade. My tuner has done about 50 tune revisions for me. It wasn't a case of him not wanting to work more. There was no more power to be found so he didn't adjust the tune. He has the other 49 times so the issue is not him, it's the hardware which simply doesn't make the car faster.
Anyhow hope that helps. The DP robbing top end power is a different discussion, but all of that was also documented back in the day. Dig for it or just trust me.