Unfortunately for my beloved readers I have not found a competent history of mergers and acquisitions. I have been involved in several myself and I have helped prepare businesses to be sold.
What happened in the late 1950s was that several corporations began to form conglomerates. The conglomerate was a core entity that bought other corporations that were well run financially. The core entity ran the acquired companies by controlling the finances. Using capital and financial statements the conglomerate was able to manage the associated companies.
In the process, more and more companies achieved corporate management standards that created a market for the buying and selling of businesses. The businesses on the market began to resemble a supply and demand environment. Businesses, over the next 40 years found it easier than ever to buy and sell other companies.
People in the M & A field developed an expertise for the buying and selling of corporations that made the market quite liquid. This was a major change in the nature of global business.
I know of no one who has reliably written about this high level, highly productive change in corporate management.