The cost to start and run a business should depend (and change) with how many businesses are in the region.
As more businesses start in a region, the costs should rise. If there is just one factory in the USA then the costs would be lower then if there 1,000.
Maybe not. The business utility costs / set up fees would probably reduce, but the costs for sourcing parts would rise as shortages hit.
In a crowded retail market the cost of effective marketing would rise but to achieve that effectively in game marketing would have to be a visible factor on sales results and the price / effect would be shown in the planning window (of course changing based on what others are spending)
This is a tough one because arguments could be made on both sides. And we need to be careful not to overly disadvantage new players since our game will constantly have new players join all the time.