A documentary on the royal family reveals that the late Princess Diana worried about Prince Harry for this definitive reason.
In the 2013 Netflix documentary The Royals, royal expert Jennie Bond noted that the late princess feared her young prince would be looked over by not only the family but outsiders as well who might have believed his value wouldn't be as important as his older brother, Prince William.
"Diana always told me she was a little bit worried about Harry. She was worried that he would get overshadowed, that he didn't have a proper role if you like. This is always a historic problem for the spare. You have an 'heir' and you have a 'spare,'" explained Bond.
Princess Diana died tragically in a car accident in Paris when Harry was just 12-years-old.
This series also made claims that Princess Diana felt it would be difficult for Prince Harry to make a difference as a younger son since the bulk of the work for the family and the most importance would be placed on Prince William and his future wife, who would eventually inherit the roles of king and queen of England.
Prince William married Kate Middleton in 2011. The couple has three children: Prince George, Princess Charlotte, and Prince Louis.
There have also been rumors suggesting that Prince Harry is jealous of Prince William because the latter is second in line the throne, reported International Business Times.
Just last year, Prince Harry revealed he has no interest in becoming a future king.
"Is there any one of the royal family who wants to be king or queen? I don't think so, but we will carry out our duties at the right time. We are involved in modernizing the British monarchy. We are not doing this for ourselves but for the greater good of the people," Prince Harry famously said in 2017, as reported by Express.