Of course, as a start-up you base your valuation on potential in the future, which should be well calculated based on how capable your employees are, how innovative your product is and what are the expected earnings.

Do you think Anthropic is still a startup? That's an honest question, Wikipedia certainly seems to think so, (Anthropic PBC is an American artificial intelligence public-benefit startup founded in 2021.). I would typically say that once you have 61B valuation, you have to have a fundamentally sound business, and thus cease to be a startup, but I don't know where the line is drawn.