In my experience, I’ve not seen anything that has been put into the engine as “experimental” removed from the engine completely.
There should always be caution used when developing with a experimental tool because, as you point out, things can change drastically from that first implementation to what may eventually be the finished tool. There is potential for some of the features to be merged, added to, or removed. This is often why it is not suggested to work in development of your project with these kinds of features, but that is just a warning and shouldn’t stop you from releasing your project necessarily.