While the FPGA is interesting, the whole "offload the main server resources" thing gets a bit moot when you do that by adding more resources but on a separate board in the same box.
Either we'll get more composable hardware where you essentially get smaller versions of what mainframes are where your mainboard is just a service processor and your actual storage, compute and I/O is just added on top, or we'll just get more CPUs on the mainboard and IPU/DPU goes away again.
In a way it's the cycle of the thick-client towards thin-clients and back again, over and over. The only real reasoning with what is happening in the IPU/DPU space seems to be the rather rigid/non-flexible "standard" server shapes and specifications where it is really hard to build composable hardware without resorting to just putting it on PCIe cards. Maybe once we have gone all the way back to the "it is just a backplane" we'll return to "mainboards" again.