We have discussed this topic on HN a number of times, for example:
http://news.ycombinator.com/item?id=2735537 http://news.ycombinator.com/item?id=2006749
Many of the comments in those threads do a better job summing up than I ever could. However, briefly, literally all of the incentives are aligned against publishing code and data.
If a writer's code is wrong, they are embarrassed (and there is no culture of being embarrassed by not publishing code).
If a writer publishes their code and it is actually good, someone else can scoop their follow-on results.
If a writer does not publish their code, and it is actually any good, they can potentially commercialize it thanks to the Bayh-Dole Act.
If a writer publishes their code and people intend to use it, the writer needs to clean it up, check it for correctness, and handle support requests. These activities are probably more time consuming than writing the code in the first place.
If the writer publishes their code, and other people in the writer's field do not, the writer is usually at a disadvantage. Others will appear to have more publications, the basic currency of academia. (Many people have great reasons for not publishing their code or data, especially researchers embedded at large companies making changes to large proprietary systems.)
So overall, yes, it would be great if CS paper writers gave out their code. What they are doing is not reproducible science in the philosophy of science sense.
But what is Jacques (or anyone else) doing to fix this system of incentives, and what could anyone do?