MSP hub is very unlikely to go anywhere for the various reasons already mentioned. Fortune 500 count is just one of many factors that contribute to international demand. Tourism, population, overall business environment and business travel demands, also matter. Geography also can be a factor. Overall, considering all these factors, I'd say MSP does relatively well and that the DL hub certainly brings in more international flights that it would have otherwise (by virtue of the fact that they not only serve the O&D market, but also connecting traffic).
Philly has similar fortune 500 count, but has significantly more population (6M) than MSP area and likely overall more businesses. It also benefits from geography in that it is significantly closer to the many large population and business centers along the eastern seaboard where it can pull in connecting passengers and it is also closer to Europe. The overall population and number of businesses in upper midwest where MSP primarily draws from is smaller and MSP has significant competition for this traffic with the larger ORD. DTW benefits from being closer to eastern seaboard centers and the population and business centers in the Ohio Valley.