Well, the motivation to make something obviously depends on how many lines you have, and how much worth they are to you.
One of the first invites the FPC core team had by a business was sb who had a source to source compiler because he had over a million lines in the source language (that he wanted to convert to Free Pascal). He invited the FPC core team to basically get info on constructs that were still not translatable and wined and dined us for a long weekend.
That nobody/hardly else in the world (still) used that source language didn't matter one bit for that.
The product was afaik a db server integrated with an application framework.
Anyway, the question is are there such very large high value codebases in Xojo/RB?