The friends-of-friends change happened in 2014. Cambridge Analytica's method stopped working back then as apps could no longer acquire permission to query friends of friends.
Someone can still write an app to distribute on FB, and can use its platform's ability to foster virality to make it take off. That's a core feature of FB. The change you're talking about, if indeed it was made, may reduce the speed of vitality a tad, but wouldn't really affect the ability for an app to spread virally.