A lot of people tend to forget, comparing SC's timeline of development to other AAA games doesn't work when those games are pushed out early, rushed to the finish line by publishers who don't care about polish, only sales numbers, and are fine with compromise at every level.

Chris Roberts doesn't do compromise. Every system in SC is created for hyper realism, down to working hydraulics and gears for the moving parts of ships. He wants everything to be perfect, and he'll call it done when he's happy with it.

And like you said, it's technically playable right now. I've never before been part of an alpha development, able to make posts about bugs that actually get read, commented on, and fixed by the dev team. Most game "betas" are just a 3 day early-access where nothing will actually change.

The game is hyped up so much because we see the potential, enjoy playing what we can, and love having a say in it's development.