Andrew Carnegie started his "work life" as "child labor" in a cotton mill. His path from "poor immigrant labor" to "wealthiest man in America" included the three "high tech" industries of the 19th Century - telegraph, railroad, and steel.
Carnegie Steel united several smaller steel operations in 1892. Mr. Carnegie became the wealthiest American in 1901 when he sold Carnegie Steel to J.P. Morgan (well, it would be more accurate to say he sold to a "group of investors lead by J.P. Morgan").
Working in a 19th Century steel mill was a dangerous job - and there were some "labor issues." How responsible Andrew Carnegie was for those issues is debatable.
The implication that Carnegie Steel (or any steel company of the time) INTENTIONALLY paid low wages is "historian fallacy" territory. Obviously if you try to apply "modern labor laws" to the time then EVERY factory looks like a low wage death trap.
Compare Carnegie Steel's labor practices to the 12 hour days, 6 days a week, $1.20 a week pay that Mr. Carnegie made as a 13 year old - and Carnegie Steel looks generous.
Steel was in exceptionally high demand in the late 19th/early 20th centuries - innovation, organization, and an in demand product was what made Carnegie Steel profitable.
Carnegie Steel became U.S. Steel after Mr. Carnegie sold the company. The libraries Mr Carnegies philanthropic efforts built tend to be "historical preservation" candidates in the 21st century ...