Not sure I agree here

Text is just human thoughts in their most simple form. Writing is about expressing ideas, and there is almost an infinite number of ways to express them. Extremely difficult task, and LLMs only "imitate" it to the best of their training

This is not at all true for voice. There are an infinite number of possible voices, but a finite number of tones and phonemes you can use to express the text.

It's a much easier technical problem; it's just that it's much harder to gather proper data (you cannot just scrape Reddit and hope for the best, as LLMs do). And voice gets like 1/100th of LLMs' funding