After he died, I read his screed, all 140 pages. I was very curious.
1) He had anti-social attitudes which prevented him from making social contact with people. He never put in significant effort to make friends or have a girlfriend, he made micro-efforts here and there that didn't lead to fruition and then he would give up. This was true from an early age, as he writes that his step mom would beg him to leave the house and interact with others rather than play Pokemon all day. He wrote of her like she was a nagging woman, an angry b**ch, but as an outsider I'm seeing a woman who was desperate to help him and fearing the future.
2) He was entitled and wasn't willing to make the effort. For example, he talked to two girls in the streets once, they didn't respond to him well so he threw coffee at them. A criminal act. He went to one party, it didn't go well, so he tried to pick a fight with the women but men intervened and then he got injured. He just didn't try very hard and didn't make the investment necessary. Another one was weightlifting, he figured that with more muscles he would get more women. He quit weightlifting after three weeks because he didn't get enough results. He thought about getting rich by becoming a screenwriter, he wrote that he had ideas for science fiction movies, but he didn't even write 10% of a screenplay as it looked like it would take decades to land him success. He tried to apply for part-time jobs, but he thought the jobs available were not worthy to a man of his intellect. He also dropped out of school.
I don't recall him trying online dating.
3) He had high standards. He wanted "hot blondes".
4) Being rich and good-looking by your standards won't go that far for somebody like Rodger who grows up in a well-monied community in Santa Barbara. The standards there are much higher.
Here's my review of his screed, which I wrote back in the day: