With some hardware skills, one can upgrade / replace the internal storage, though this only goes so far.
Problem is, there are newer, cheaper and better devices with faster storage and higher memory bandwidth, so the market on more recent (non-obsolete or non-vintage) Intel Macs holds steady (for legacy compatibility purposes), while anything that lacks Thunderbolt 3 / USB-C ports becomes a liability.
The last time I saw this was during the transition to Intel chips: PPC G5-based devices fell off the face of the earth within a couple of years, with older G4s holding up the rear for legacy (Mac OS 8.x/9) compatibility. It's a plateau.
As a Mac and Linux user this is my concern, my old Macs have always been repurposed as Linux computers once Apple drop support for them, extending their lifepsan but it's getting harder now especially with Apple silicon. Asahi is an option but it's also easy for Apple to block if they wanted to in the future.
You can’t even get a Mac Mini with 64 gigs of even -unified- RAM much less program ram. Upgrading this thing feels like such a scam.