The phrase, "reconfigurable computing," seems to bring to mind flexibility and freedom of choice.
It seems natural that some of this flexibility should mean that developers will have all the information to target whichever programmable logic device that is best for their designs.
In the FPGA world, since understanding the structure and format of bitstreams and how they are formed could mean exposing intimate details of the device to the world, from a chip manufacturer's point of view, divulging less is understandably more desirable.
Unfortunately it also means less people can work on improving software tools for implementation--map, floorplanning, place-and-route, bitstream generation.
There are few open standards for apples-to-apples comparisons as well.
It is almost like the software industry of the 1960s-70s, when big companies dominated the scene with proprietary formats and tools.
- Compilers were hard to write then, but they became easier and eventually standard, open source ones like the GNU C Compiler came along
- Software was mostly written in-house and few believed it could be out-sourced
- Personal Computers and sharing of IP were almost unheard of
One could argue if the software industry has evolved for the better or for worse since then, but I certainly enjoy being able to write a program on my laptop, compile it and run it right away without so much as a simple installation of Linux and gcc. Come to think of it, Linux would probably have not become what it is today.
Perhaps one day every piece of electronics would really have a generic programmable logic device and one could just write a program to run on it without having to download and install proprietary tools, search too hard for suitable IP(More of sites like http://www.opencores.org and http://www.rmdir.de/~michael/xilinx/ please) and learn too many different tool interfaces.
Without going too much into the merits and demerits of open source software / hardware, I tend to think that going down the path of open sourcing FPGA architecture and software would lead to greater engineering benefits. For business reasons, more clarity may not be a good thing perhaps, or at least business models would have to be tweaked for many companies who are used to the current models in the FPGA industry.