Companies want stability. If my plan is to raise $2 billion with an IPO, I want to be able to build a business knowing that money is coming in. With an auction, I wouldn't know how much money will come in. It might be $4 billion, or it might be $500 million.

The current structure has a financial intermediary who charges a premium to take the risk of a price DROP for me. I can shop around for who will give me the best price, and once I've got that locked in, I know my $2 billion will come in, and I can start building my engineering, marketing, etc. with the stability of a guaranteed check in the bank.

That stability is worth more than the premium.

Why do you think this would work? Google IPOed with a dutch auction, and went on to pop 30% in the first 2 days.

An auction allows you to find a market-clearing price, but does not allow the information-exchange to do proper price discovery, so it doesn't solve the problem. The IPO pop is typically explained as the reward for taking the risk of buying an unpriced asset.