Gemini is really good, dev is happy, cost is low, but the mass just don't use it, The UX feels...weird(in my opinion), and Google marketing just sucks. Look at the craze of GPT-4o image gen launch, Pretty sure none of that will ever happened with Gemini(which tbf, have extremely good imagen too!) They have weird too-careful-and-afraid-to-step-on-someone-toes approach to marketing, and that shows.
OpenAI have Sam as 'presenter' that people can hear him talk enthusiastically, Grok have Elon, even though that not really help much. Gemini? just AI product from faceless mega corporate. People don't feel relate to that. The emotion is part of equation of why people use something, not just function.
Also doesn't help with ChatGPT name already cemented in AI history. Every Bob and Jane heard about ChatGPT even they're use it once, but Gemini...who?