Comment by FireBeyond

There is someone on YT (Doctor Feng, or similar, though I can't find) who literally will have people ship him entry level iPhones/iPads/MBPs, etc, and he'll upgrade them to 4 and 8 TB SSDs. And create ASMR videos of the process.

Even with upgradable memory:

When I bought my "cheesegrater" Mac Pro, I wanted 8TB of SSD.

Except Apple wanted $3,000 for 7TB of SSD (considering the sticker price came with a baseline of 1TB).

I bought a 4xM.2 card and 4x2TB Samsung Pro SSDs, which cost me $1,300. However, I kept the 1TB "system" SSD, which was faster, at 6.8GBps versus the system drive's 5.5 GBps.

Similar to memory. OWC literally sells the same memory as Apple (same manufacturer, same specifications). Apple also wanted $3,000 for 160GB of memory (going from 32 to 192). I paid $1,000.