There are investment fraud prosecutions literally all the time, they just get 5-10 years in prison usually, not life. They aren't on national news because few people know the scammer or the victims.

Here are a handful from this year alone:

https://www.courtlistener.com/docket/67034239/1/united-state...

https://www.courtlistener.com/docket/66964256/1/united-state...

https://www.courtlistener.com/docket/66760869/1/united-state...

https://www.courtlistener.com/docket/65767429/17/united-stat...