Well, let the Itch faq confirm it for you ;-)
https://itch.io/docs/creators/pricing
If someone pays for a project, they are granted ownership to it. If they skip payment, they do not get ownership, and can only download the files. This is important to be aware of if you decide to convert your project to Paid at a later time.
Usually all this works fine, it is just something to remember when changinge prices. Upping the price of an individually priced file is a bad thing. Having lots of 2 $ donors and a 10 $ item, one might not want to give that item to the 2 $ donors, but maybe it is a work in progress and this is precisly what is intended to make it future proof and have one paid version and one free version of the game.
If someone has a problem with this, that person should view it this way: the early supporters got the game while it was on a sale. And in a way that is exactly what happened, if the page were converted that way. (To my understanding of the faq).