Monopoly structure rocks, I don't think it deserver half the bellyaching people give it. Building multiple lvl 1 factories is a poor mid-late game strategy. You should plan your industry from the ground up, concentrate the base industries (lumber, steel, fabric, cement) in 1-2 states each and then concentrate the more refined ones in a similar fashion. Depending on the country you're playing you may be making a lot of clothing, furniture, luxuries, steamers etc.; but plan it out in advance as well.
This way, after the year 1850 95% of your factories built are expansions of existing ones. Some of the benefits here are building at 1/2 the cost, being able to concentrate capitalists for maximum efficiency, better industrial score and tighter control of your industry. Want to shut down clothing production and switch it to, say, telephone gear when it becomes more profitable? No problem, build then expand telephone factories right next to your clothing ones and shuffle workers across as they're built. Easy, and the capitalists are already in place.
Monopoly structure is a godsend for countries which do not traditionally make their fortune chiefly through colonization like Austria, Russia, Prussia, the US. Yes, they can colonize and monopoly hurts them there, but they'll benefit much more by investing in their already populous domains at home so that they're able to flex their muscles later and take any colonies the need from others around them.