Just for sake of realism I publish this smart map from Forbes
This a world map where countries are resized according how many cos' they have among the world 2000 biggest (according Forbes)
You make it sound like owning conglomerates is a good thing. But the US has proved over the last 4-5 decades that the future doesn't belong to the conglomerate. It belongs to the small business.
Which provides more jobs for the US? Conglomerates or small business?
But the problem is that that is grossly misleading. Italy, for example, has long had tax laws that discourage large corporations -- so whenever corporations get too big, they spin-off divisions. The United States does have larger corporations than other parts of the world, but that ignores the fact that vast amounts of economic activity take place regardless of the fortunes of very large corporations, and that smaller companies are often more nible than their larger competitors.