It's because some large percentage of your time at work is spent in meetings, writing emails, discussing things, etc. where actual ability to do the core task isn't necessary.

And then some large percentage of "enterprise software development" is just hooking up buttons and text fields to a database, and doesn't require any more algorithmic complexity than a few if() statements.

And then some large percentage of the remaining work can be performed adequately by just picking some appropriate ready-made solution off Stack Overflow.

Put them all together and chances are, you can skate by for years (and actually perform acceptably) without ever actually needing to write FizzBuzz-level code for yourself.