I read an interesting comment the other day as there was an old piece of writing I did awhile back for a project where I simply published it for free as it was something I thought would be fun and educational. It got a good reception apparently and to this date it still generates a lot of views. Recently though there was this one comment from a person thanking me for writing it and saying how most people would have probably made it an e-book to try and profit from it and that maybe I should consider that.
I never created an e-book personally even though from what I have seen it looks pretty simple. I must say though, it would be too weird taking something that you provided for free in this case to then simply take it off and say that people will need to buy it now. It’s a little different if it was like giving live advice for free where people start demanding so much of your time that you need to start making a living out of it.
I don’t think I have ever met a person personally who took say publications that they offered for free only to then take it down when it became popular to then monetize it. If anything I would think you would only want to do that for future work.