Power production is only one facet that needs to be considered in the potential of these engines. Weight is a huge oversight, these cars are 1000lbs heavier than their contemporaries at the drag strip. Look at every Fox-body, G-body, or F-body that is effectively running a hopped up LS with the same power on stock bottom ends. That 1000lbs takes a massive load off the drivetrain - and if you don't think it has an effect you are delusional. The cylinder pressure in boosted engines is astronomical, and exacerbated by anything it works against (and this is nothing to say about the effects of aerodynamics).
I have a pretty decent amount of experience with boosted LS and Buick V6 engines using stock cast pistons (stock ring gaps), stock cast or powdered metal rods, and stock cast cranks. The Hellcat engine has basic forgings in all of those locations which aids in reliability in a factory forced induction application, and this does nothing to suggest it can support more power than provided from the OEM. Look at the HC engine: it has a factory 11.6psi of boost (a stupid measurement which fails to account for mass air flow) - rule of thumb is that each PSI is worth 30-50hp (it is a diminishing return as pressure rises and the abidatic efficiency of the PD blower lays over in the higher rev range). Figure 11.6 psi x 30hp = 348hp, subtracted from 717hp = 369hp; which means that a 9.5:1 NA HC motor makes approximately 370hp from its 6.2L. This is within the realm of possibilty, noting that the base engine and gains from the forced induction are likely higher as there is a known quanity 80hp pumping/mechanical power drain from operating the supercharger under load (also the SAE testing of the 2019 HC is showing 747hp crank). This is precisely consistent with the gains on a NA LS or Coyote engine with a power adder; after about 800 wheel whorespowers they all become time bombs.
In both instances (factory cast or factory forged internals) you are rolling the dice by doubling the power with forced induction, however when you put it into a land-yacht and penalize yourself with an additional 1000lbs of ballast your window for error narrows significantly. The saving grace for the HCs is the better, not great, factory internals. This is why I bought a HC, not to make superstar power, but have a beautifully engineered package that I can enjoy without worrying about driving over the crank (which is allegedly 1400hp capable in the HC, hence the need for a drop in rod and piston set for more reliable power) as designed. The margin of error was taken into account before it left the factory, remove the safety seal and all bets are off. It is like poking holes in condoms.
Two guys with success on the internet is not a sufficient sample size, and I put little credence in the actions of others. The same goes for every shitbird who cannot drive their car worth a damn and standing there with an "I dunno wha happen'd" look on their face when they do 3 gear full-out cool-guy burnouts (and just dump off the throttle at the end) to impress other people. These cars are marketed as performers with high-levels of potential in the right hands - the common denominator in all failures and poor performing HCs are the jackasses piloting them. Which are the same fools who toss money at Stage 11 durr... durr... 1000hp packages and have no appreciation for what it really means. People need to do their research, manage their expectations, and have some fucking accountability for the decisions they make.
A supercharged V8 is a beautiful thing. Keep good fuel in it, respect its inherent design limitations, and cut the weight down where ever possible (especially reciprocating mass in the driveline).