From my basic understanding of Bell labs, the government granted AT&T a monopoly in communications with the condition that they spend a portion of their revenue

From my basic understanding of Bell labs, the government granted AT&T a monopoly in communications with the condition that they spend a portion of their revenue on public research. The other labs I don’t know much about, but my guess is it was either similar situations or high corporate tax rates incentivizing spending profits on research to decrease their tax burden.