Yeah, there is very little reason to want to do this. It may become more of an issue if new SATA/SAS drives stop being produced anymore for maintaining those legacy systems - but at that point something based on an FPGA (as was suggested in another comment) is probably going to be more economic than a company bothering to spin an ASIC for the purpose. But I don't see SATA drives dying out for a fair while yet.

Usually the tail end of legacy systems are adequately supported by new-old-stock for quite a while.

e.g. 3.5" floppies are 40 years old, were obsolete 25 years ago, went out of production 15 years ago, and are just about ready to deplete their stock today. Yes, there are flash-to-floppy adapter, and a similar thing may happen for SATA, but we may not see that as a necessity until 2050.