I do understand why companies often prefer BSD and Apache products to the GPL.  But what I don't understand is why companies prefer proprietary over GPL.  Let me emphasize, I'm talking about a product that is not related directly to core business secrets such as content management or a database.  

The first reaction is, "with the GPL, we must make our changes publicly available."  But I would ask, how is that different than a proprietary product, at least in a negative way?  For instance, if we spend $100,000 on an IBM product, we have directly or indirectly paid for the development of that product.  If we pay for IBM to enhance that product, we have directly paid for the development of features we find valuable.  IBM will continue to sell that product to anyone that will pay, including our competitors.

If there is a competing GPL product that would require $50,000 to customize, and $50,000 in ongoing support (let's choose numbers that take cost out of the equation), most companies will take the proprietary route every time.  

In the GPL case, you've spent $50,000 on features you find valuable.  Indeed your competitors can now use that product and those features, but they can in the proprietary route.

There are additional benefits to the GPL products that seem to get overlooked.  We have full access to the source code.  We usually have a community full of examples and solutions to any problems we may encounter, which are only a Google search away.

Even fiscally, there are benefits.  We received a big chunk of value for free to start out with.  In the future we will, for free, be "paid back" in contributions from other parties.  For instance, other parties may fix bugs in code that we contributed.  Other parties may add features that we can now use (without the upgrade charge of the competing proprietary product).  Also, contributions to an open source product can earn us good publicity and good-will among developers.

Further, I would suggest, contributing to GPL will help in technical recruiting.  I believe many of the best software engineers are more likely to work for a company that uses and participates in open source software.

The reason companies stick with proprietary products, I suspect, is comfort.  We are comfortable buying products from vendors.  We know it, and we understand it.  The new world is a frightening place because we aren't as familiar with it as the old world.