Sony's strategy is getting as many people as possible on their consoles as quickly as possible. because they get a cut of everything each consumer buys on the playstation store combined with playstation plus. They're not doing that at $649, especially with this economy. The ps5 pro is sold at a profit so that's not an accurate representation of what the ps6 price will be. The are willing to subsidize since they are going to get a cut via software. The only way they continue their success next gen is not going above $550, $500 would be even better.
The ps6 will also use smaller components than the ps5, a deliberate choice to reduce costs. A $500 digital ps6 would do very well since a bunch of people buy digital nowadays and $550 would be for the people that still buy physical. $500 seems to be the cutoff price in general though. $550 is a test. Not $600 and above $500. Sony could of bumped the price to $600 and chose not to, because of what occurred with the ps3. They want to see how well that sells compared to the $500 digital ps5 to determine whether or not a $550 ps6 would sell well. That's why there are rumors of a delay because they don't want to price the ps6 too high and ruin their strategy.
Sony discontinuing both the ps5 and ps5 pro and concentrating on the ps6 sold at the the same price as the ps5 to cut costs would not be surprising. The ps6 will probably play ps4 and ps5 games so this wouldn't be detrimental. Sony wants previous gen playstation users on the ps6 and they have been trying to get those users off of there for a while now since have yet to buy a ps5 after almost six years. That's not happening at $649.