I would argue that almost every industry has been increasingly monopolized. Look at the historic number of players in every major industry - it's indisputable that the trend has been towards consolidation, not increased competition.
What's more - the companies that dominate various industries are majorituly owned by the same financial entities, which in turn own each other.
Think of the biggest players in each industry, and search to determine who owns the most stock in those companies. You will find the same organizations over and over again - Blackrock, Citadel, States Street, etc.
That's likely because you are looking at the US and not globally. And it also depends of you are evaluating the total number or the total number that control say 50% of the market.
And when people think of large industries the look at the large players and ignore the much larger market behind that. And industries that are very distributed, generally are not perceived as large industries, despite them being very large, like hotels or food.
Also Blackrock for example is 170 billion, that's about half a % of US GDP and like 0.1% of global GDP. so if after 200 years Blackrock is the best example you can come up with, I'm not convinced.
And the companies Blackrock are owning a stake in, are still competing with each other, because companies like Blackrock can't control all those companies.
Think of the biggest players in each industry, and search to determine who owns the most stock in those companies. You will find the same organizations over and over again - Blackrock, Citadel, States Street, etc.