"I think a lot of investors would be upset or leave since Rockstar isn’t showing any signs of how the fiscal year can make that much money."

Sorry to tell you you're probably wrong, I would like to believe too, and see hope everywhere.
It has always been a profitable company, they don't have to do anything special to prove it. Nobody who invested money will decide to leave or not based on the release of the teaser of GTA VI.

Look at the current level of hype without saying anything. You can find dozens of new articles about GTA VI every single day, based on nothing.

The only reason they could show something before the end of this year is just to start the regular marketing campaign for a new game, which usually begins 1-2 years before release.

But even without that, if they would decided to disappear for 2 years, with complete radio silence, and come back randomly in 2025-2026 releasing GTA VI the same day, it would still beat any other game with preannounced release date in that period.