I actually dont see any evidence that Sony would do that, they know that the high mark is around $500 (inflation not withstanding) regardless of competition, we have the PS3 to thank for that which even Sony admitted was a huge mistake in regards to its price. I actually think the PC market will keep them in check also.
$90 games on PS5 compared to PS4 is evidence. charging for online is evidence. Consoles are priced competitively is evidence itself. A company will charge the most it can get away with charging compared to its competitors. That $500 mark is way out of date as a high mark.
PS will have their USP with their own exclusives (as well as the Xbox third party stuff) so, price doesn't need to be a differentiator between them and the competition (multiple OEM Xbox machines). I have absolutely no doubt Sony will price themselves in the pack with those other guys. Where is there the motivation to carry on the tradition of losing money on each console sold when they would be the only competitor doing that? They won't. It's like charging for online. When one starts it everyone follows because that sets the median from which all the main competitors then set their own business plan. If no one else in the space is subsidising consoles how can Sony justify doing that to their shareholders? Lets be honest here, Sony increased the price of games by $10 this gen and did that have any effect whatsoever on sales? If they add $200 onto the cost of a console BUT that console is still competitively priced amongst its peers then they are not going to sell less purely based off that price. Sony are a business, businesses are there to make money and other than feelings there is no logical reason to carry on subsidising console hardware. Sony will not leave that money on the table.
Please explain why a PS6 that is $200 (it could be more or less but lets just call it an arbitrary $200 for the sake of argument) cheaper than the competition is going to make more profit than say a PS6 that is $50 cheaper or the same price when it will already be able to play the same games as those others as well as it's own exclusives. Surely a product that can do everything the competition can do and more on top should be priced higher not lower according to market forces?