He is 60 years old per wikipedia, this is likely his last rodeo. He has held board positions at Datadog, Athena Health, App Dynamics and other places in addition to his job at Mongo per LinkedIn. He was also at Mongo for 11 years.

It seems he is deeply connected, and probably approaching centimillionaire wealth.

Even if he is burning some bridges, its not going to affect his career at this point.

Edit: I looked at the current interim CEO's profile, not the outgoings, but its almost the same story- he is 55, been on other boards, has experience at director+ level since 1995 listed... this isn't going to hurt his career.