To an extent I agree. The general purpose language has been very successful because there's sufficient commonality between the operations that a lot of program

To an extent I agree. The general purpose language has been very successful because there's sufficient commonality between the operations that a lot of programs enact (what is good for one is good for the other) but the DSL has been also, perhaps a lesser extent, because of the benefits of specific optimisations you mention. That's my balanced observation.