Why is it so hard to get a job to be an FBI Profiler?

Mainly because it does not exist- there is no job in the FBI called "profiler". The FBI does have the Behavioral Analysis Unit which provides behavioral science and psychological analysis of criminals and crimes, but there is nobody there officially called a "profiler" (although similar work is done).

It's part of the National Center for the Analysis of Violent Crime, which is something of an expert referral center for the FBI that provides expert opinions on cases. As such they aren't hiring a vast number of people most of the time and often a job only comes up if someone retires.

Shadow. All agents have university degrees.

Not all in the BAU are agents, About half are academics and retired/working homicide detectives.

None normally go to a real scene nor do they get to fly in a private jet. They do not make arrests in the cases.

They simply review the evidence and make suggestions as to who or what type of person would have done the deed(s).

Used to be they did not include real police but they found that the FBI agents relied on statistics and past actions of those who have been caught and interviewed for their opinions. They started to include real experienced police when they found their method to be faulty in many cases.

Because agents spend an enormous amount of time pretending to do surveillance.