Like yourself, I have considerable experience in working with, and writing, fairly sizable pieces of computer simulation software in a variety of languages. None of what I have worked on is remotely comparable in complexity to a major climate model, of which I have merely used the outputs...which was plenty enough work on it own.
The very thought of making my data and model available in any usable form makes me quiver. I have tried to do this once or twice, and it takes a huge amount of effort. I just can't see making such availability a requirement for all scientific working groups. Their actual research productivity would grind to a halt.
At least, that is my opinion, based on my experience, which may well be less than yours.
I am in the last steps of preparing a paper and I am, for the first time, undecided if I am going to make the software available (the data I won't, as it can be generated from the software with not much computing power). Just bundling the software is a major pain and I am pretty sure no one will care to repeat my stuff, so I probably will skip it this time. If I submit to PLOS Comp Biol, they will probably force me, but other journals, I very much doubt.
They should force me.
