"Yahoo!'s value will never recover"
Yup, it's a crash & burn, and it feels richly deserved.
This billion-account breach occurred in 2012. Instead of communicating on that issue, Marissa spent the next year with other priorities, such as redesigning the logo, and not securing an email backdoor.
Well the problems are finally coming home to roost. Looks like you still can't avoid a problem by ignoring it.