I think the beneficiary is wrong here. Those teens will grow up to work for organizaitons using Azure AD, Windows, Office and OneDrive/SharePoint/Teams.
If any company is going to get the windfall of "AI provider by default" it is going to be Microsoft. Possibly powered by OpenAI models running on Azure.
Google could make a "better" (basically - more sublime) advertising platform but little to attract new users. Perhaps Android usage would rise - Apple _is_ behind on AI after all. On the other hand, users will either use the AI integrated into Excel, Word, PowerPoint, Teams, Edge and more, or else users' AI of choice (ChatGPT) will learn to as competently drive the Windows and Web UIs as Claude Code drives bash, giving a productive experience with your desktop (and cloud) apps.
Once you use _that_ tool, its now where you start asking questions, not google.com. I am constantly asking ChatGPT and Claude about things I might be purchasing, making comparisons, etc (amongst many other things I might possibly google). Microsoft has an existing interest in advertising, and OpenAI is currently exploring how best go about it. My bet isn't on Google right now.