"Just with The Simple Life, I was just over it. I wanted to just focus on my business," Hilton told ET's Kevin Frazier on Wednesday. "They have huge business empires. I am sure they want to spend their time doing that and being with [their] families."
Hilton said she hasn't spoken with the Kardashian-Jenners about ending their show, but assumes "they have so many things going on." "And after 20 seasons, I think they are ready to just live their life and not be on camera every second," she said with a laugh.
The heiress and entrepreneur is sure fans will still see the Kardashians out and about and possibly on streaming services -- "Kris [Jenner] is such a boss," she raved -- and she's happy for all the success they've achieved so far.
"It makes me feel incredibly proud. I have known [Kim] since we were little girls, and the empires that she and her sisters and her mother have built is just amazing," Hilton gushed. "I love them all so much, and it's exciting to see your friends do well."
Hilton has stayed close with the family, and Kim even appears in her upcoming documentary, This Is Paris. The film, directed by Alexandra Dean, covers the trials and tribulations Hilton has gone through in her life, including a very traumatic experience she had at a young age.
"I wanted to show the world the business woman I am and the empire I built," she told ET of why she's revealing all in the documentary. Her traumatic experience came out "naturally, because I felt so comfortable with the director," she explained.
This Is Paris dives deep, and explores the origin of the "Paris Hilton" many fans think they know.
"I think people are going to be very surprised when they see this film and see sides to me that they've never seen before," Hilton shared. "Even the people who do know me don't even know some of the things that I talked about in this film."
"It's going to be very surprising and shocking to people, and then I think also it's going to have people understand me a lot more," she added.
This Is Paris premieres Sept. 14 exclusively on YouTube. See more on Hilton in the video below.