That's an idea we've thought about. However, we think the open source community has already created a very impressive set of language or region-specific finetunes [1] [2]. Also there is a lot of cultural and nuance context in every language that we don't have the capacity to cover sufficiently. So for v3 we focused on creating the best foundational multilingual model.
[1] https://huggingface.co/aiplanet/buddhi-indic
[2] https://ai.google.dev/gemma/gemmaverse/sealion