That would result in a much larger download, too big for many users with slow internet/limited data. At the moment, the total file size would be more than 2Gb so bigger than many people's limit on Mega
It would actually be smaller than the total combined file size of the separate versions,
due to redundant code/images.
Merging can also be a time for devs to go back and fix/improve any issues in earlier work
(i.e. maybe a fuzzy render, or some inefficient code written when they were less experienced, etc)
Ultimately, it's one of those things with benefits and drawbacks and is up to the dev.
Personally, I came looking to see if there was merge talk, because I had let a few updates go by
to build up content, and now I don't remember if I was in part 2 or 3 last time I played.
So, a merge would be a good excuse for me to start over and then never have to worry about that problem again.
