I am wondering at what point will governments step up and regulate social media, loot boxing, and other such digital-based addictive things just as they regulate other addictive things like drugs, alcohol, and gambling?

When the current generation of politicians are dead or when something sufficiently drastic happens. It took EA being incredibly abusive with lootboxes in a game from a series as popular as Star Wars and the resulting backlash on Reddit going viral for some politicians to consider some investigations. Actually getting them to work on it seriously would take something even more drastic than that.

it's been in argument for years. I don't think the US will ever step in given its culture.

Also, I'm unsure how you step in and "regulate social media" to begin with. The whole issue is that social media provides much of its content via users, and users take these bathroom writings as gospel. That's a societal issue. Even if you regulate the money out of social media people will just join some home spun sites or even the fediverse, and the core problem continues.