We all know about fear of failure, but fear of actually succeeding and getting what you want is very real too.
By and large, we're all addicted to our mental patterns. It's on us to explore them, get out of the ones that don't serve us and create new mental patterns (i.e. working out 5 days a week no matter what, creating a habit of approaching any female you find attractive, etc.)
A dude can scream from the rooftops that everything will be different if he just gets over this one problem and that he wants something so bad, but it's his bad habits and actual fear of getting what he wants that makes him make those crucial mistakes that keep him stuck.
For instance, the dude who wants to be a famous rock star might start showing up late to the studio, trashing hotel rooms and letting his vocals get fukked up right after signing that record deal he's wanted ever since he was a kid.
The reason is that even though we claim we hate being broke, womanless etc., there's most definitely a "comfort" zone there, even if you hate your circumstances. So many people will choose their known shytty circumstances, as opposed to stepping into the fear of having to become a new person and take on the unknown things that come with that.