all the out-of-order execution occurs inside a single CPU
adding more CPUs won't help speed up a single-threaded program

picture a call center
an attendant is like a CPU
the attendant can pay attention to one customer at a time. the customer may issue multiple requests/instructions, and an attendant with out-of-order operation may be able to look into and satisfy some of the requests before other earlier ones
however, adding more attendants wouldn't help this one customer get faster service, unless the customer started multiple calls (threads or processes), or the attendants could pass customer requests and context on to each other (that's not permitted by the call center design; they can only transfer entire calls)