Because a huge part of their business model over the past twenty years has been the upsell.
I bought my first MacBook in 2007. It had 2gb of RAM as standard. I asked about upgrading it, the guy told me to pick some up online as it would be waaaay cheaper, and he was right. Did the same for the MacBook Pro that replaced it a few years later, but in the meantime they moved to the soldered model so had to swallow the cost of the 16gb ‘upgrade’ in my M2 Air.
To be fair, the cost over time of my Macs has been incredible. My 2011 MBP is still trucking along, these days running Linux Mint. With the cost to upgrade the RAM and replace the HDD with an SSD, all in it cost me around £1200. Less than £100 a year for a laptop that still works perfectly fine.
