"First of all only the cellular stage could be relatively simply ported over to mobile. All the other stages will need major control scheme changes, mechanics changes and probably a ton of extra optimization etc. Then there's the fact that none of the users libraries have been selected explicitly to work on mobile platforms. And may of them don't officially say they support any mobile platforms (including the graphics engine). So it would be a ton of work to either replace them with ones that have mobile support (though, in my experience most libraries are either mobile or desktop platforms only, there's very few that support all), or adding support in them for mobile. So it is probably only slightly easier to add mobile support than making two complete games.
Additionally if by "mobile" you mean iphone, then that is even more complicated as we current programmers don't have macs, which are needed for iphone development (I also don't have an iphone either, but I don't know if some other programmer has one). So very unlikely, but I won't say never." - hhyyrylainen on reddit
A newer post about this is here: https://www.reddit.com/r/thrive/comments/jb5tub/mobile_version/