I wouldn't believe you, because in 2002 Clear Channel had a large radio division, Clear Channel Outdoor and Clear Channel Entertainment.Do you know how many employees there were 20 years ago? What if I told you the number is about the same now as it was then.
Also, according to SEC regulatory filings (page 12 of the annual report), iHeart has 10,800 employees, of which about 9000 were full-time as of February. So please stop with the 18,000 employees bit.