More commonly attributed to Eugene O'Neill: https://www.google.com/search?q=%22Success+is+a+stale+finale.... A playwright would be more likely to use the word "finale", and in any case the thought is too modern for Spinoza. But most probably it was neither of them—quotes like this are nearly always misattributed.
"The journey is the reward"
- Steve Jobs
As long as the journey contains ethics (no Spinoza pun intended) from DRM to discarded children.