#1 There would be no mainstream American wrestling on television
Without Stone Cold as it's star, there would not have been the Austin-McMahon feud which did more for the company in assisting it in vanquishing WCW as it's competition than anything else.
With the WWF likely to go out of business, that would have left WCW as the only game in town.
However, Austin's exit from the WWF wouldn't likely have changed the course of history too much in how WCW was run during their 1999-2001 demise, as that was based almost entirely of their own in-house factors, and an ageing roster.
The AOL/Time Warner merger would likely have still gone ahead and WCW would still have been booted off cable television by Jamie Kellner. WCW was still garnering decent ratings, though they had dropped significantly since their 1996-98 peak. If there was a will to keep WCW on the air, it would have happened.
Former WCW boss, Eric Bischoff's attempt to purchase the company may have gone ahead without the WWF in existence, but so damaged was the brand name, it's unlikely this would have been successful even without any competition. Bischoff proved in his tenure with Impact Wrestling in 2010 that he had not learned from his mistakes.
In a terrifying prospect for fans of professional wrestling, WCW's inevitable demise would have left no mainstream wrestling promotion in the United States.
Jeff Jarrett would still have set up TNA/Impact Wrestling but they and never have had the budget to become a global force on the scale of WWE or WCW and could not have afforded the Triple H's, Undertaker and Kane's of this world.
Any fan of professional wrestling would likely have had to watch New Japan or All Japan, which is likely where many of the major American wrestling stars would have ended up.
In 2018, no one would know the names of John Cena, Randy Orton or Batista. It is incredible to think how one botched wrestling move could have changed the course of wrestling history so significantly that it would almost have ceased to exist.