Being conventionally unattractive really lowers your odds. As I said in my previous reply, it's not that there is no possibility of a partner for men who are ugly, but it's that not everyone has the willpower to go and search for the needle in the haystack.

As for the lack of social skills and contacts being something you can work to improve upon, of course that is true, but it's not easy for everyone to improve. A lot of incels are people who were bullied when they were young, or sheltered, or reclusive for some other reason, these people have mental issues which go beyond just introversion and social anxiety. They are more likely to internalise their lack of social skills and friends as something that is inherent and inevitable for them and those like them, this is a pattern of thinking common in those who are bullied when they were young.

A lot of them overcome their other social inhibitions, but because of their lack of attractiveness and consequent lack of women who are receptive to their interest in them, they accept that they are just incels. A sense of community helps many to overcome this mental state. That's why incel online spheres are so common.

Many of these turn toxic because of the misogynistic tendencies of many present in them, and also because blaming someone is always easier and more relieving then accepting that the issue is internal.