It is indeed a long time and a fair thing to bring up. Without getting into a philosophical discussion about sentences in general though, I think it's fair to point out that she ran a fraudulent company for well over 11 years, benefiting personally and financially from it all, while knowingly doing so, lying, and whatever else. She fired an employee who tried to warn fairly early about her lies, who later committed suicide. She hired investigators to follow Tyler Shultz around and bullied him with lawsuits.

These and more actions of hers do make me personally feel okay with her sentencing, especially since she shows zero remorse. Her final words before sentencing were basically "I'm sorry I ran a failed startup".