https://www.gamespot.com/articles/destiny-2s-exotic-drop-rates-will-be-tweaked/1100-6462130/

The latest expansion to Destiny 2, Forsaken, came with some notable changes to Exotics. Since launch, though, Bungie has heard feedback from fans that the pursuit of Exotics isn't working quite the way it intended, and so it will be taking steps to correct the loot drops. However, that doesn't mean the battlefield will be raining Exotic gear left and right. The drop frequency will remain essentially the same. Instead, Bungie plans to increase the chances that an Exotic drop will be one that you don't already own.

In a blog post, the investment team explained its reasoning. "Exotics are intended to be meaningful long-term chases," it says. "Finding an Exotic should be rare but impactful. Right now we are falling short of the 'impactful' part of our goal. There's nothing exciting or powerful about getting your fourth Fighting Lion when all you really want is a Two-Tailed Fox. We plan to increase the chance for Exotics to drop something you don’t already have."