Apple Drops Mac SSD Upgrade Pricing 

It’s about time, as SSD and memory upgrades are Apple’s single greatest markups, far surpassing the original suppliers retail cost. For items like an iMac’s memory, it’s still cheaper ordering the bare minimum installation and upgrading it yourself, but since Apple now routinely solders these components in place, this is bitter solace for most.

Very well put, Apple really wants to limit the amount of upgrades that people do outside of the store. They want to control everything end to end.