Thing is, these were intentionally created as experiments with the expectation that they would be eventually shut down, with whatever learnings integrated into the mainline apps.
Since about 2017-18 there has been a unit at Facebook called NPE, New Product Experimentation, tasked with producing these.
NPE was created in 2017.
Facebook had "Labs" in 2011-12.
The same idea keeps showing up again and again every few years thanks to a hugely profitable ads business.
Since about 2017-18 there has been a unit at Facebook called NPE, New Product Experimentation, tasked with producing these.