Why has economic inequality important became a more prominent issue in last ten to fifteen years?

Prompt; Why has economic inequality important became a more prominent issue in last ten to fifteen years? What role has government played in increasing inequality? Do lawmakers give preference to the concerns of certain groups over others? What impact does lobbying and money in politics have on lawmakers? Use all 4 sources for the essay; 1. https://www.opensecrets.org/influence/ 2. ://2012books.lardbucket.org/books/21st-century-american-government-and-politics/s13-02-lobbying-the-art-of-influence.html 3. https://robertreich.org/post/9789891366 4. https://promarket.org/2019/02/26/governments-responsibility-rising-inequality-tools-reduce-it/