What’s important is not so much being world class in your field of expertise (although I strongly reccomend it). The key variables are passion, effort, and will.
The passion to truly love whatever it is you do to make a living.
The effort to push yourself, and reach new heights within your field.
The will to never give up on your field of expertise just because of a few cloudy days.
These are the things that will make you unstoppable, and eventually well respected when looking back on your legacy.