Glossing over the fact that they probably wouldn't have all of those 1.5 billion users if it had stayed a paid service. Even at $1, having to pay money pushes people off to other free platforms.
And a mobile messaging company relies on the network effect to stay relevant and popular.
They could try charging $1 per year now and see what happens. Probably a flood mainly to Facebook Messenger and in part to other apps.
Every user of these so-called free platforms pay way more than $1 yearly for using them, via products they have been pushed and attention they have lost. If you're a potential high-wage earner, you're paying more than that in an hour!
The tiers you suggest don't affect any layperson (would your grandmother even know what geolocated ads are? Would she care?). If anything, it sounds alarming to a layperson to even have these options.
IMO your comment is a clear example of why technical people should not always be the product decision makers.