The vast majority are done because of the inconvenience of having to care for the child.
It goes beyond that, it is life changing, more than an inconvenience, it can also be life threatening. Calling it an inconvenience trivializes the situation. I know of more woman than people realize whose pregnancies nearly killed them.
I don't expect you to understand, ever, unless, you marry and your wife faces such inconveniences, like the placenta separating from the uteran wall, or gestational diabetes or dehydration from vomiting to the point of hospitalization. My girlfriend's first baby nearly killed her, they decided to have no more but her husband refused to have a vasectomy, she practiced birth control, but tragically became pregnant,again, using contraceptives, she aborted, and the decision was devastating, but necessary with a young child to think about and her health, was this an inconvenience, hell no, it was her life.
You don't know the personal stories, you just think you do.