Some of the things that make getting the job so hard are:
Difficult Entry Requirements for College Graduates
Product Management is not really being taught in colleges since it is a relatively new position. There are a select few colleges that are teaching product management classes, but there are not many. There are ways you can get into product management from college, but it is not an easy road. You can read this blog which describes steps that can be taken while in college to get into product management.
The supply exceeds the market. There are too many people who want to be a Product Manager and there are not enough positions being offered that satisfy the job market for Product Managers. The barrier to entry is high, so this makes the market very competitive. It can be so competitive that people might just apply to any Product Manager position that they see.
A position can be open for months if the interviewers don’t find anyone they like that fits the role. The interviewing process is extremely long as well since there are usually four rounds of interviews that the job hunter has to pass in order to get an offer. You can go to 10, 20, 30 or even more interviews and not pass any because they will decide on another candidate or say that you were not a good fit for the position.
To even get the interview you have to pass the recruiter’s test. Because the market is so competitive, the recruiter has to go through maybe hundreds of applications per day. There will be some things in your resume that stand out to them and there might also be something that deters them from contacting you.
Since it is so hard to get the job for most people, the constant rejection can make you feel incompetent and dejected. It can be demoralizing and maybe even make you give up. However, persistence is also key to getting a Product Manager job. The interviewing process becomes its own skill for you after you go through them enough and eventually you can land that job.