Complex sentence: However, CGI has made up for the expenditures by grossing over 20% more than their real-life counterparts, and by the early 2000s, computer-generated imagery had become the dominant form of special effects.
Split into simpler sentences: However, CGI has made up for the expenditures by grossing over 20% more than their real-life counterparts. In the early 2000s, computer-generated imagery became the dominant form of special effects.