Ads don't make much money, like somewhere between $10-15 per 1000 views on average. If you consider how long some single player games are, say 50 hours or 3000 minutes, that is 1 ad per 3 minutes of gameplay to save $10-15 on a 'lite' version.
wattur
joined 10 months ago
Look up incremental / idle games. They're basically 'afk games' where you press a few buttons, buy some upgrades, plan a strategy, and then come back minutes/hours later and spend accumulated resources on upgrades and repeat.