It's practically a religion at HN that early-stage companies that are not currently earning profits are somehow 'lesser' than more-mature profitable companies. However, this misconception is neatly illustrated in BioNTech.

BioNTech went public with a market value of ~$3.5B, solidly into unicorn territory, despite losing a tad over $100m the prior two years. Through the typical business lens, this makes sense as they were in investment phase hoping for a potentially large payoff as their product matured. The IPO gave them the capital they needed to realize their vision.

Obviously, they are worth a lot more now because that narrative was correct. Should they have been more conservative and only expanded R&D at a pace supported by their revenue?

You're right, but this kind of stuff is actually much more rare in "tech". Google, Microsoft, Facebook, Apple were all quite profitable (GAAP) at their IPO time, which was also earlier than today's standards. Look up the old S-1s if you want to verify. It is very common in biotech, though.

Yes, companies used to wait until they were making money to go public, but they have more options now. My larger point is the capital stack a company chooses to fund its growth is a function of its particular business and market, along with the investment climate. (For example: companies stay private longer now because there's far more private capital available than in 1980 when Apple went public. There's no one right answer. Amazon would likely be a much smaller company if it had maintained profitability all along. Perhaps would not have produced AWS, which bled oceans of money for a long time.

For every Google or Facebook (arguably two of the best business models in history), you can name an Amazon, Netflix, Broadcom, DocuSign, Square, or Tesla. Success comes in different flavors.

(Tesla notably spent something like $10B before getting to profitability. This is an artifact of the intersection of their market and their global ambitions. Unlikely they would have had the impact on major auto manufacturers as a much smaller, profitable, boutique firm.)