That is unfortunate, because these are special skills you may but find inhouse. I know some guys that did it inhouse for a long time, toured from project to project in the right phase and saved bigcorp lots of money. Now they are doing it publicly.
Usually large companies attract or develop these skills by their scale. I do think there a lot of smaller companies that are underserved in this area, though.
There are a few "optimization startups". But in this context I find it a bit ironic that pretty much everyone is working with the same architecture, and the same hardware for the most part, so actually there isn't really that much demand for bespoke optimizations.
Those that are serious are paying through the nose for their engineers to work on these optimizations. Your competitor working on "the same hardware" does not magically make your MFU go up.
And when you have enough spending to account for 1%+ of revenue for the AI hardware companies?
You can get the engineers from those very hardware companies to do bespoke optimizations for your specific high load use cases. That's something a startup would struggle to match.