3, by far.
1. There exist incels from upper-middle-class backgrounds who experience a degree of social isolation far worse than their more attractive counterparts from lower socioeconomic classes. I am one of them.
2. It's unlikely that incels as a group have decided that there is no purpose in maintaining a stable career and income outside of caring for a femoid. Rent, student loans, and credit card bills still need to be paid. I rely on alcohol and other copes to get through the motions of life; surely a $0/year income won't support that lifestyle?
3. It's been well-documented in the psychological sciences that your attractiveness influences a professor's, or a potential employer implicit judgment of your ability. More attractive individuals have been constantly praised all their lives; which, in a society where confidence is often conflated with competence, has negative effects for unattractive individuals such as yours truly. Ugly individuals are effectively locked out of client-facing roles from the moment of their birth.