That's a good point, Marty.
A lot of the time, design and development in different countries coincides because of programme requirements.
All the major players in aeronautic design have borrowed heavily off each other over the years. None want to waste time and resources re-inventing the wheel, so they tend to build on known science.
In the case of the Shuttle and Buran, the mission requirements are the same, externally they are quite similar, with differences in the way they actually function.
I guess the way it goes with design, someone has to be first, then someone else improves it, or if the original design is sound enough, it gets copied.