This amusing cartoon by Geek and Poke captures one of the important reasons why so much of our planned software reuse fails. Thus projects often fail to achieve the economy of scale benefits from the business case.
Within companies there is often little trust between departments and an unwillingness to rely upon things that other people have built.
The real question is how can we overcome this problem so as to achieve the benefits of shared resources and reuse?
The first step in resolving the problem for any organisation is recognition that this kind of problem exists. The next step is to bring the issue out into the open.
Often there are war stories within the business that explain how or why the lack of trust has evolved. It is important to uncover these reasons. Once things are out in the open they can be managed.
My rule of thumb for problems with technology projects is that about 70% of the problems are in our heads (us being all the people involved in the project), while the other 30% of problems are logistical (e.g. stuff takes longer to do than planned; or stuff gets delivered late).
Very rarely are the problems actually about the technology in and of itself. More often the problems that appear to be technical result from hidden issues with people that remain un-addressed, or architectural problems that lead to the selection of inappropriate hardware or software.
By Carruthers via Aide-mémoire