It's because companies are far more obsessed with power structures than with actual output. This is especially true for public companies where the grift is to get into positions of power, propose "initiatives", find scapegoats for failures, then hop on to another company - leaving a trail of damage behind.

In my experience, the only time a company does well with structures is when there are fewer levels in the org chart and when the C-Suite penalizes management before ICs.

Doesn't happen very often though.