Why are some talented people left out even though they can prove themselves when given chance just because they don't have experience?

having a job experience in the specific field or line of work is an edge.
it will guarantee the employer that the applicant is qualified and has a training and experience fulfilling the task or job that was given to him/her.
moreover in our society nowadays, even if your talented company will always go to the one with the experience due to the fact that they believe that talent is useless without proper training and experience

I have to be honest and clear with , according to the vacancies needed and its requirements from the employers as some vacancies need experience and others not according to the employers decision ,Also I want you to put yourself as an employer if you need and experience person in the vacancies you published will you agree to hire any one in this job even he / she got talent but no experience ,I think the answer will be NO for you business safe wise, finally I wish you always put yourself in the position of decision taker and not as the person who is applied for any vacancy.

In the structure of society, there are already many people who have experienced ,have had a lot of career and have been at high positions.
They don't bac down and would like to remain their possition.
So, many capable young person couldn't get even important opportyuity.

Learning is basic.
Passing thoery doesnt mean you have everything.
Practicallly things are completly different.