I think the new factory high horsepower cars are just part of the cycle of change I have seen since riding in or driving cars since the late 60's and early 70's.
In the early 80's the fastest car I owned was my 74 Nova. It had a 350 and 4 speed with roughly 400 horses. It had plenty of power and was quick. With the gearing it was a steady 13-14 second car at the strip. This was on open car nights, stock street tires, just some fun times with friends and trying different tune ups to see how it affected speed. Nowadays if I still had this car my Sister's Camry would give me a run for my money and out corner me without much effort with the ac on! But back then with the available technology and cars available, the Nova I had was competitive and equal to many other performance cars on the street.
Back in 85 200 hp or close to it was becoming the norm as far as performance cars were. 10 years ago 300-400 hp seemed to be the norm. Now anything with 500 hp is looked at as "oh thats all" kind of mentality thanks to ZL 1's Hellcats, Demons, etc.
Unless something catastrophic happens to the economy I see the factory performance market growing still. There is always room for improvements and is there any true ceiling for hp when it comes to the true car nut?
My favorite shake my head moment is how some Hellcat owners are all bummed out because of the Demon. My goodness you think the world was coming to end. All of a sudden words like inadequate, not good enough, just not the same anymore, were being said about a 707 hp factory car! I never in my life thought I would see the day a 700 hp car was inadequate! This just begs to ask if many of these Hellcat owners are true car guys or just spoiled brats that have to have newest and best of everything and are never happy or satisfied? The cars themselves are not ruining the hobby, it is the type of owner getting these cars and by their stupidity on the road making all of the true enthusiasts look bad.
Most of the above is just my opinion based on seeing cars change since the late 60's until now and just like many other trends in society today, we can see the good in most of it, but there will always be something or someone to give it a negative turn. I am just waiting for the day I can put a 600 hp electric motor in my SS that weighs 100 pounds total with batteries and charges the battery packs in 5 minutes. Sounds crazy now, but 10 years ago I never thought I would see a factory built type car like a Hellcat or Tesla that can go sub 3 second 0-60 mph times with a full warranty and high tech systems. And with cup holders!!! lol