From UX Matters:

There are various reasons why usability problems exist in the first place-some simple and some complex. Identifying problems and recommending solutions is not always enough. Unfortunately, the same factors that cause problems in the first place also hinder their getting fixed. The following are some of the most common reasons why usability problems don't get fixed.

“Identifying problems and recommending solutions is not always enough. Unfortunately, the same factors that cause problems in the first place also hinder their getting fixed."

Everyone should read this article.