You're not wrong, but it's important to keep in mind that for more complicated FPGAs, they have hard IP blocks in them often supplied by other companies. Also consider that when these IPs have errata in them, they can sometimes be worked around with FPGA soft logic. Oh, and parts of the software are supplied by companies like Synopsys.

As far as I am concerned though, Synopsys is essentially Autodesk, and Blender is taking over!