That's not really how this should work. Mainly for the reason that SO MANY early access games just disappeared after making enough money during pre-alpha. Happy to pay $5 for EA and test the game and give feedback. But if you pay full price and the game is in alpha or beta for a year that's not really cool. Would also be happy to pay $5 for EA and then full price on release. But you don't get to play the game "more" as most feature are not even included or games are buggy before release.
Again: Happy to support indie games but charging full price for alpha or even pre-alpha is a bit ridiculous