> He's been doing this every 4 years since the 1980s. Announce, use the free publicity, drop out.
Factually, no, he hasn't. While he has overtly considered running in 1988, 2000, 2004, and 2012 (which isn't every four years since the 1980s), 2016 marks the first time he has formally announced a campaign.
Ignore him.