We see the alternatives in the handful of cases in which spying on users isn't a viable model (or, at least, just doing that isn't viable). Typically it's directly paying money for services, maybe with a free tier (Github) or something Free with a capital F and community-driven (Wikimedia). Take away spying and serving deceptive/harmful ads as an option for e.g. search, mapping/route-finding, voice recognition, and so on, and we'd see alternatives pop up, probably under those models, or possibly under more traditional less-invasive (and less malware-spreading/scam-promoting) advertising models (like magazines, or the early ad-driven web but with way more eyeballs).