I hear you. There is obviously a lot of tension between price and performance. I think the introduction of boards with larger and larger ram specs really pushed the cost just before the pandemic and then scarcity spiked things even more. As when I purchased the rpi4, I got the maximum RAM and that became expensive.

However, SD Cards are really terrible devices to run a general purpose computer on and they are designed for storing large files like photos, videos and mp3’s sequentially not the SWAP, logs, and databases that a full operating system is constantly writing and accessing in a random fashion.

I think if you are running a base 2gb, then maybe absolute value makes sense, but once you start hitting the larger RAM configutations, an M2 slot is a no brainer.

I think the cheapest working SBC is really the zero line.