> Very true as well, and if that were plainly stated the problem could be addressed.
That's not, at all, how this works, especially for newcomers.
If the new programmer on your team doesn't want to work on a larger code base, it's your responsibility to notice this early, initiate a talk with them about the reasons and actively try to fix the problems they have.
Reading code is hard enough, but reading it under pressure of being the new guy makes it even worse. Don't expect many people to be able to cope with this without serious effort on your part. If you can't be bothered to effectively support them in understanding your code, they are not likely to care about that code sufficiently to productively work on it.
That's not, at all, how this works, especially for newcomers.
If the new programmer on your team doesn't want to work on a larger code base, it's your responsibility to notice this early, initiate a talk with them about the reasons and actively try to fix the problems they have.
Reading code is hard enough, but reading it under pressure of being the new guy makes it even worse. Don't expect many people to be able to cope with this without serious effort on your part. If you can't be bothered to effectively support them in understanding your code, they are not likely to care about that code sufficiently to productively work on it.