This is the point of Itch's "pay what you want" system exactly. People pay if and what they want and can, as you rightly said, this is an optional payment feature, it doesn't force anything on anyone, the game is still available free as long as you allow anyone to freely enjoy it and leave to them the choice to reward you if they want/can. ;-)
Hey, my friend, did you actually download a game available free from Itch? Because I often do and I can tell you that it doesn't go as you describe it, there is no "0$" to select, when you click Download Now, Itch says "This game is free but the developer accepts your support by letting you pay what you think is fair for the game." then the player has 2 options, either click on "No thanks, just take me to the downloads" if they don't want/can't pay or pay what they want and can if they want and can pay. The point is that Itch makes clear that the game is free and that the player is free to pay what they want if they want/can. It works more like a spontaneous donation than a payment per say. :-)
Also, Itch's "pay what you want" system applies to Itch as well as each developer is free to choose if they want and how much they want to share of their income, the payment feature from developers to Itch is just as optional as from players to developers, this is what I call freedom and why I love Itch so much. ^L^
I don't want to just give you some of my money, I want to buy my own copy of Renryuu Ascension, this exchange is meaningful to me. Moreover, I don't like the patreon system which gives favor to people who pay over people who don't pay, this system creates inequality between players who pay and players who don't pay, making the game not really free as players who pay get more attention and get more out of it than players who don't pay, even worse, the game's development itself is influenced by players who pay, meaning that the game is influenced by money, this is no different from being influenced by a publisher who funds the development so this is not really indie development to me, I don't like this system which makes money have influence on development and so I don't want to support it.
Hey, Naughty, you already knew how much I am fond of Renryuu Ascension, I already got in touch a lot with you about it, didn't I? ;-)
Actually, I am so fond of Renryuu Ascension that I wish to help you develop it.
I was waiting for the good moment to talk to you about it and since I am expressing you how much I love your game and how much it inspires me, I think this is the good moment to tell you about my dream.
It has been a while that I have been dreaming of becoming an indie developer because video games are part of me since I was a child and I have been having a lot of ideas for creating new video games.
Remember the ideas that your game inspired me to enhance it that I shared with you and that you liked and added to your to-do list? ;-)
This is my point, I want to become an indie developer, I am fond of your game so I want it to be completed as soon as possible, it inspires me ideas that you like to enhance it, you have an endless to-do list to achieve, which requires a lot of time and energy, which I can share as much as you need, I want to help you achieve Renryuu Ascension because I like it and I want to get to experience it in a fully satisfying way with nothing missing and nothing lacking as soon as possible, I am determined to help you to achieve it, I also think that I can learn from you since you already have experience in game's development, you could teach me how to do things then I would help you to do them, which would be mutually beneficial as I would alleviate your workload while I would earn experience and we would double the efficiency of Renryuu Ascension's development since we both would dedicate time and energy to it, which would benefit to everyone waiting for its completion. :-)
So I have many good reasons to want to help you achieve Renryuu Ascension, I am determined to do it, I can afford to share a lot of time and energy to dedicate to it since what I want to do is become an indie developer and I am so fond of your game that I wish to work for it through to its completion, I can give you many good reasons to be interested in sharing your workload with me, and I think it would benefit everyone.
So? :-)