Why does this nonsense phrase appear in so many old newspapers?

Check out my PATREON: HUGE thank you to my PATREON SUPER SUPPORTERS: BIG SUM Carson W Wesley Snipes Christopher Kukla Kevin Beck Dave Hurley Rob Myers Azuth Nekomaencer Aidan Patko MananaHammock Todd Unkefer Archduke Beatleboy62 B.R. Yeager Lynsey F McCoskey Mike Hochanadel An Coopín LegitBinary Dean Jones Tyler Holden Slaton Spangler Sean P Kristina Emily McKenzie Pam Goodridge Preston Hill Austin Baker Patrick van Dijk Conor Johnson Daniel Monsalve micky! Kyle Jonathan Hays Alexander Morgan Anastasi Andrew Reda Jason Farque Russ Determan Daniel Lano Cody Armacher Aaron Greig Drkek Jason Morrey Jeffrey Hacker The Grand Poobah Lottie Hew Jeremy Chase-Israel Will Surrette LepcisMagna Luke Fuller Sam Markey Josiah Parker crocoalala Joseph Walla JB Riley Flamingo --------------------------------------------------------------------------- ETAOIN SHRDLU! The phrase that struck fear into newspapers for almost a century! --------------------------------------------------------------------------- References/Further Reading: Altoona Tribune - November 27th, 1939 The Scranton Times Tribune - November 9th, 1895 Tri-County News - July 3rd, 1970 The Herald-Palladium - March 10th, 1978 The Chippewa Falls Weekly Herald - January 25th, 1897 Des Moines Tribune - June 13th, 1970 The Calgary Herald - April 27th, 1966 The Llano news - February 22nd, 1961 The Calgary Herald - January 16th, 1971 The Vancouver Province - December 14th, 1935 The Bladen Enterprise - August 24th, 1934 Journal and Courier - April 24th, 1929 Sequoyah County Times - February 20th, 1942 The Rutherford Courier - March 30th, 1934 The daily commonwealth - November 25th, 1916 Dallas Morning News - April 12th, 1925 The Grand Rapids Press - June 8th, 1969 The Flint Journal - June 1st, 1969 The Fort Wayne News Sentinel - August 7th, 1954 The Anchorage Daily Times - January 17th, 1946 Richmond Times-Dispatch - May 12th, 1974 Des Moines Tribune - June 13th, 1970 The Boscobel Dial - May 14th, 1970 The Calgary Herald - April 27th, 1966 The Mechanism of the Linotype - John Smith Thompson, 1916 Omaha daily bee - March 11th, 1917 The Raleigh news & observer - November 17th, 1895 The Linotype Bulletin, Volume 17 - 1921 Fort Worth Star Telegram - June 22nd, 1975