Google’s Gemini app has just joined an elite club: one billion users, and, according to CEO Sundar Pichai, the fastest-growing product in the company’s history. It is the 14th Google product ever to reach that scale — a number Pichai shared proudly on social media, calculated from usage across Gemini’s app ecosystem.
Yet the milestone lands at an unsettled moment for the team behind it. Demis Hassabis, the Nobel Prize-winning scientist who has led Google DeepMind’s public identity for years, has stepped back from running the lab day to day. He is not alone in leaving the front lines — Jeff Dean, whose engineering fingerprints are on nearly three decades of Google’s technical infrastructure, has also departed, along with other senior researchers.
The exits come as Google’s next major model, Gemini 3.5 Pro, remains conspicuously absent. Promised for a June release, it has yet to appear, even as competitors roll out systems many in the industry regard as more capable — particularly for writing code, currently the most commercially valuable frontier in AI development.
What Google still has, and what it is now leaning on, is scale. By weaving Gemini into Search, Gmail, Google Maps and YouTube, the company can convert its existing, enormous user base into AI adoption without needing to win on raw model performance alone. That dynamic — audience as advantage — is playing out across the industry.
OpenAI announced its own billion-user figure in July, spanning all its interfaces and led by ChatGPT, though it did not clarify whether that reflected weekly or monthly activity. The company built that audience from nothing in under four years, since launching ChatGPT for free in November 2022 and igniting the broader AI boom. Every user metric OpenAI can point to strengthens its case ahead of a possible IPO, for which it filed confidentially in June.
But the ground is shifting beneath the early leader. ChatGPT’s share of the AI assistant market slipped below 50 percent in the first half of the year, according to estimates from Sensor Tower, as Google’s Gemini, China’s DeepSeek and Anthropic’s Claude all cut into what was once OpenAI’s uncontested lead.
