Let's contrast two addictive and harmful phenomena in order to see what's controlled them and what hasn't:
1) Cigarette smoking: In the last 50 years, the % of adults who smoke has fallen dramatically. WIN.
2) Slot machines: I don't have revenue numbers, but I'd be surprised if the $$ figures have fallen by anything like smoking's. LOSS.
Internet addiction (and smartphone addiction) IS harmful. If you disagree with that, you can probably stop reading.
If you're still here, we can agree it would be very good to decrease addiction, even if it'll never disappear entirely. How?
For smartphone addiction, we can publish a few articles like OPs, or make fun of addicts, but it'll probably turn out like slot machines. The addicts don't care what we think of them.
For smoking: cigarettes were never actually outlawed -- adults can still buy them. So what worked and how could it be replicated?
1) Massive public pressure and education, so smoking became uncool. This has barely started on smartphone addiction, so bring it on.
2) Outlawing smoking in all public places. Covered below.
3) Restricting for youths. Also covered below.
4) Taxes: a pack of cigarettes is massively taxed.
5) Lawsuits, like the state attorneys general filed against the tobacco companies.
Now, for public places: it's possible that certain apps could be rated by some agency, public or private, as "addictive" or "distracting." The app makers would fight it like hell, but too bad. The literature on how they're addictive is pretty voluminous now.
Once we have a legal designation of Instagram or TikTok as "addictive" the way is open for indoor spots or schools to prohibit them, make them illegal to use while driving, or for the app makers to restrict them for children.
Would this work on its own? Pretty imperfectly, but the effect of social apps being rated "addictive" even if some are not rated yet, combined with the education program, would be large.
I haven't covered (4) and (5) yet, but this posting is already pretty long!