The insane pricing for for RAM and SSD upgrades I would argue do skew a lot of margin to higher end systems still though.For the M1 Apple has largely left the system prices the same while the Intel mark-up disappeared. They have also dropped the higher profit BTO choices. That wasn't to take in less money overall. They are just cranking the higher margin take to the whole product line instead of skewing it to the top end BTO systems.
+$360 to move from 16gb of ram to 32gb or +$720 to move to 64gb is nuts.
32gb of RAM should be around $200, and they are technically taking away 16gb as well worth $100. Essentially you are paying $460, or 2.3x retail pricing for RAM by going through Apple. > 100% margins is brutal.