I switched to monthly subscription model from lifetime and my conversion rate tanked!

I created willpayforthis.com which accumulates social media posts from people talking about products they'd pay for.

I really want to be on a monthly subscription model so I can track retention and learn from it, but the retention tanked when I switched from $30 lifetime model to $20/month subscription model.

I guess I really didn't understand my user. I'd love any input this community has.