Problem is Apple didn't offer a non-BTO model with 16GB RAM. In some markets, we only get whatever baseline Apple offers, no BTO options, in this case all of them only comes with 8GB RAM.
I believe they did what made most sense for most users. There is only that much RAM you can cram onto a package, and offering different package sizes wouldn't make sense economically (since you will also most likely need a redesign logic board). Focusing on the intended market segment (entry-level) and limiting the RAM to what is appropriate for that market segment is a reasonable choice when you consider the alternatives (which would basically mean significantly increased cost).
It is a shame that users who need more RAM are not served by the M1, but their Apple Silicon Macs will come later on. They will use die stacking or some other technology to offer more RAM with higher bandwidth.