I agree with your premise,

If we want to truly find peace and comfort with the life that we are living, we should have our own independent definition of ‘success’ and how it is achieved.

in as much as it would surely help lower the anxiety and frustration levels people may develop as the result of unfulfiled expectations. That being said, there are obvious results in any field that are supposed to provide a minimum of financial, emotional or social security.

Take Steemit, for instance, where being a whale (or at least a dolphin) seems to be a commonly shared goal that would distinguish the average steemian as a successful member of this ecosystem.

We know how difficult achieving such goal may be, unless you had money to invest a priori or some friends or allies that help you ascend that ladder quickly.

Most Steemians may set up less ambitious goals and just enjoy the ride, become content creators and participate of as many communities as possible, learning and sharing as you'd do in any other social network.

Even if at some point there is a moment of questioning about the profitability of the amount of time devoted to Steemit and the actual dividends it generates, people can find satisfaction in the very content that was created and which would not have seen the light had it not been for all the interaction generated here.
That may mean success for some, and that's better than a frantic pursue of finacial success that may very well leave irreparable damage in the process.