The reasons are not hard to understand and are explained in the first post in this thread - there simply are not enough developers on the team to expand into adapting Corona for another piece of software. To do so would mean taking people away from the existing teams and dramatically slowing down development of Corona for Max and C4D, which we are not willing to do as we have too many established users relying on us and the software. No-one would be happy with one release every 2 years, or releases in similar timeframes as current but which had half or a quarter of the features we normally put into a release, and the impact to development time would likely be on that kind of a scale.
We are not willing to compromise on our support of our existing user base, and this means we are not considering developing Corona for any other software, sorry.