Given that we see this type of behavior in all industries (not just tech), it seems to me it's actually a systemic problem. People / organizations are incentivized universally to optimize for their own selfish interest, because they do not incur the cost of their decisions on everyone else. In this case, designing your product to maximize e.g. addictiveness or time spent per user makes sense if the downside of that is paid by the user.
I think taxing wealth / property instead of (primarily) income actually solves this problem, but that's another story...