"It's this world that's so much more satisfying," Rosenberg said.
Rosenberg gave up computers for … cats.
Somewhere around 100 cats, to be exact. At a swanky cat sanctuary he built in New Jersey, he's loved cats for years - and he put his money where his heart is, CBS News correspondent Richard Schlesinger reports.
Roughly how much of his money has he spent on this project?
"Ah, somewhere north of $2 million," he said.
The sanctuary is named for one of the great loves of his life: Tabby, his cat of 15 years who died in 1999. Rosenberg never met a cat he didn't like - and some of the cats hanging around his sanctuary are tough to love, such as one named Jackie.
"She'll act friendly," Rosenberg said. "You can pet her for five or 10 seconds, and then she'll go after you."
Sure enough, she attacked.
All of the cats there come from shelters and were scheduled to be euthanized. Not all of them are troubled, but a lot are.
One cat, Mozart, has what is politely called "urinary issues." Another, Tashi, has back legs that don't work. He gets physical therapy.
Another one, Star, is actually allergic to people.
Obviously, it can be hard to find homes for some of these cats but it can be done. About 550 cats have been adopted - and more than 100 of them have been, so called "special needs" cases.
If they're not adopted, all of them will live out their lives with medical care and love - even if they don't really want it.
"Wouldn't it have been more rewarding for you to take cats that are easier to adopt out?" Schlesinger asked.
"No," Rosenberg said. "It wouldn't be because my heart really goes out to the cats like these, that I shouldn't say no one else wants, but for the most part no one else wants."
And while caring for cats, Jonathan Rosenberg and his wife, Sharon, were touched by humans.
"They could take this young cat, but they're willing to take this cat with heart disease, or this diabetic, and care for it knowing its going to break their hearts," Rosenberg said.
It never hurts to be reminded: Animals with some of the worst problems can bring out the best in people.