> If Google threatened to withdraw (which they're probably not foolish enough to do), the loss of things like Maps (that many other services depend on) and Gmail and Google Docs and etc. would worry most advanced economies.

It would inconvenience those who are using these Google services, but the services themselves are easily replaceable.

Google Maps can be replaced with HERE Maps, which has a similar feature set. The absence of Google Maps would also accelerate contributions to OpenStreetMap and its ecosystem.

Gmail and Google Docs have Zoho Mail and Zoho Docs as alternatives, as well as Microsoft's Outlook.com and Office 365. Nextcloud combined with Collabora Online or OnlyOffice also makes a fine FOSS substitute to Google Docs.

Any worry would be in the short term, until companies make the transition to other solutions. I agree that the absence of Facebook would also not pose long-term issues, since users would simply migrate to other social media platforms and businesses would choose other forms of advertising.