Wow, so you plan to sell everything like separate DLCs?
And there won't even be Episode 2 with a Steam Release, so people who purchase is there will be behind on content?
You do you, but I'm not buying games where content locked behind microtransactions and certanly not paying for outdated builds.
Look at other releases like Rebel Duet or Long Story Short. Steam release was one time purchase with a significant new content to motivate people buy the game instead of just pirating old build. They even put Early Access tag, so people who afraid to purchase unfinished game can refund it at any point if its abandoned.