Comment by api

This is true, but it's not exclusively limited to ad-driven models. It can also be true of surveillance or in-app purchase models. The latter has become big in gaming where games addict the user and then steer them toward purchasing special items, expansion packets, "loot boxes," etc.

Basically any app or service where there is a direct link from the amount of time the user spends on it to revenue incentivizes shady "Skinner box" addictive designs and other dark patterns.