Google drive and google photos are after that time and they both seem to work really well and be core products.

Google Drive is mainly a response to Apple's iCloud, Microsoft's then-SkyDrive, and Dropbox. It was initially an integration into Gmail, and became a fully-fledged separate product later.

Photos is the spiritual successor to Picasa, integrated into the web. It was a response and a one-up to (again) iCloud and SkyDrive which both have phot syncronisation, which is something that is missing in Android. It was initially integrated into Google Drive, and became a fully-fledged separate product just now, when the integration has been cut.

So Google's next successful product would be

1) When Apple and Microsoft has bothered to be the first, and

2) whatever is connected to Google Photos.

(btw, since Stadia has became a meme, it partially fits 1 (xCloud) but sure it isn't connected to Photos in any way)

Stadia won't be able to compete with GeForce Now anyway.