This is going to sound weird but there's this great interview with Seinfeld and Obama where they talk about the "answer" to "why do you keep doing this stuff when you're so successful and have 'made it'"?
Which I think is the real question OP is asking: "Why if I've hit this goal do I keep doing this? Why does it feel so unsatisfying?"
I've linked to the spot in the interview but the answer is to really enjoy the work and the process.
I feel this myself (as someone with a decent sized SAAS), that I still really enjoy helping people, answering support emails, getting on calls with them. It feels more satisfying than arbitrary revenue goals.