Nobody is de-tuning anything. They're tuning for a 'competitive' power figure, and nothing more which they can also build in NVH standards and meet emissions and mpg requirements, and leaving available "steps" in power increases without having to generate a new product. Hence the 370hp being bumped to 380, or the 2020/21 platinums being rated at 400hp with the standard gen2 3.5eb, whereas the new stealth performance is 440hp, 510ft-lbs, so as to not 'step' on the raptor. At the end of the day it's all towards a bottom line.
De-tuning is common when the exact (or nearly exact) engine is expected to be used in a more severe use scenario.
For example, the 7.3L V8 is rated around 430hp and 485 lb ft peak output for the F250/F350.
The same 7.3L V8 is actually detuned in the chassis cab configuration for the F600 down to 335hp and 468 lb ft because it is expected to have a more severe use case.
Also of note, the passenger car/light duty truck and HD pickup power output ratings are not measured the same way. Passenger car/light duty trucks are rated largely for transient (peak) power and not sustained power. A passenger car/light duty truck engine would likely experience more failures than a HD pickup engine if there is a peak power demand for any sustained period of time (> 30 mins of continuous peak rated power output).
I'd be wary of using an aftermarket tune for substantially more peak power if they are planning on doing a lot of towing with their light duty truck - particularly up long grades. If you're doing nothing more than 10 second pulls on a flat highway, perhaps you are not pushing the vehicle to the point where it would become an issue.
I see the appetite for tuning vary between the drag racing crowd and the HPDE/road course crowd. The former is far more likely to tune their vehicles for substantial power increases. I see far more stock or close to stock powertrains for the latter crowd. The use cases are different. The drag racing crowd is stressing out their powertrain for 15 seconds or less at a time. The HPDE/road racing crowd is demanding substantial power output over a far greater period of time (> 20 mins or more per session).
With that being said, I have a "tune" on my track car but it's to deal with the CEL from a catless downpipe. The map for the tune is completely stock. And that motor still sent a connecting rod through the oil pan which took out my steering rack in the the process after 150,000 miles with extensive track time.