How does predicting a typhoon prevent billions in damage?

It could save thousands of lives because people can be evacuated if you can predict a few hours or a day further ahead, or the path more accurately. You can save some damage by moving ships and vehicles.

But you can't evacuate buildings or infrastructure.

I know this is uncharitable and I am wrong but I am having trouble coming up with concrete scenarios where you die with 2 days notice but survive with 3. I am nonethless a believer that more accurate forecasting has value.

Valuable, agreed. But lucrative?

by giving it away they capture none of the value except for some PR.

I agree, but the shareholder mentality undervalues the heck out of that.