If you're a patron you only get access to the content that comes for your tier for as long as you give monthly.
that's literally how every patreon adult game works though. You can just wait for it to go early access once we finish Ep 6 and buy it once if you don't want to support monthly but still want to play new stuff.
We have the patreon because we're an indie studio that needs constant funds to survive. We don't have a big daddy company bankrolling us until completion.
It's not a scam, it's how we're able to afford rent and make this game for people.