Work-related machinery has no semblance of sentience and is often already supplemented by human operation. Having a massed army of Machamp, or something of the sort, in order to do heavy or skilled labor would be impractical or impossible mainly because they would all have by be subjugated by a single trainer. The human workforce is held together and kept efficient by the nature of humans to work in a society for personal and mutual benefit. Pokemon who perform certain tasks which may align with this paradigm mainly only do so because they are partnered with a trainer who also takes part in that action. So either you have a single trainer who is a sole lead of a coporation/company with thousands of individual pokemon under their control (impractical), or you just keep the same system you have in place (human labor) but supplement it with pokemon who have personal bonds with individual trainers in order to prevent them from going out of control. It's basically just the same thing as we have now except your expenses for fuel, oil and machine maintenance might be partly comprised of "pokemon food." And don't give me any of that "Earth Badge just makes all pokemon obey," nonsense. Even the strongest trainers in the franchise only have, at most, six pokemon at their immediate beck and call at any time. No single trainer is going to be able to keep a giant, highly-skilled workforce of pokemon under their heel without some sort of direct mind-control (and there's no telling whether or not that might fail at some point or what the consequences of such an event might bring).
