Correct but at the same time that overstates things, because extremely often the choice between full custom ICs versus FPGA is dictated by the expected volume of product, not just functionality considerations.
It is typically simply cheaper to deploy FPGAs in released products when the volume is small, while it may be cheaper to use full custom when the volume is in the millions to hundreds of millions, in the cases where either solution is functionally workable.
That includes amortizing the non-recurring engineering costs over the total units, which is typically higher for full custom than FPGA -- although sometimes they are actually in the same ballpark.
Aside from that you are correct; people sometimes imagine that most any application can be significantly accelerated with FPGAs, but even in the cases where fine-grained parallelism is present to be accelerated (well-known not to be the case for all application areas), the FPGA solution space is decreased by the solution space where full custom makes engineering and financial sense.
It is typically simply cheaper to deploy FPGAs in released products when the volume is small, while it may be cheaper to use full custom when the volume is in the millions to hundreds of millions, in the cases where either solution is functionally workable.
That includes amortizing the non-recurring engineering costs over the total units, which is typically higher for full custom than FPGA -- although sometimes they are actually in the same ballpark.
Aside from that you are correct; people sometimes imagine that most any application can be significantly accelerated with FPGAs, but even in the cases where fine-grained parallelism is present to be accelerated (well-known not to be the case for all application areas), the FPGA solution space is decreased by the solution space where full custom makes engineering and financial sense.