There is absolutely no law against selling below a MAP or MSRP either, what was illegal (or perceived to be) until very recently was a manufacturer cutting you off is reseller list because you didn't follow a minimum price (a form of vertical integration), that is now legal. If it is legal to cut off a reseller for selling below a demanded price I imagine it is even more legal to cut off a reseller for selling above an asked limit (thus being able for a manufacturer ready to destroy a relationship if they feel they are in the driver seat to set price limit and see if below just stop selling their product or follow them)What your referencing is MAP pricing, which is the lowest one can sell a product or be cutoff from the manufacturer. Absolutely no law against selling for above a MAP price or MSRP price point, however demand will always set the upper limit on pricing. MAP pricing is a whole other discussion tho.
Demand do not seem to set upper limit on the playstation 5 in all the big reseller, it seem to all be the same (and set at very precise market by market) and seem completely disconnected from demand.