As someone who started with a free game, added features to it, and later started charging for it, this is bumpkiss.
Yup, been there. At a certain point, you gotta at least make back your investment on time.
I don't mean the adage is false. I mean any person who ever said "I will personally pay you for this game by donating, but only if you make it free first." is a liar and a fraudster.