It is common for people to prefer no child to a child with substantial medical problems. Hence embryo selection, prenatal genetic testing, abortion, adoption etc. When one considers that it is common for parents to know someone with an autistic child, and increasingly rare for a parent to even hear of a child dying of MM or R, a prophylactic vaccine can seem not to justify the potential risk.
To put it another way, even if a person believed that there was only a 1% chance that there was a 1% increase in risk of Autism due to the vaccine, that would still be significantly more risk than death from measles. Although epidemiology is a science, vaccine sales are a business, and it is not unreasonable to weigh pharma's economic interests in vaccines that scale to the degree that MMR does. Pharma is not in general a philanthropic endeavor and a healthy skepticism regarding their products is not unreasonable.
Vaccines are generally not very profitable, to the point where the various industrialized nations are having to subsidize production to keep supply up.
Healthy skepticism is certainly good and reasonable, but what we're seeing is unhealthy skepticism. The science is in and overwhelming, but antivaxxers consistently latch on to debunked, unreliable, or outright loony evidence to support the increasingly discredited claims.
Having been around since the 1970's development costs have long since been recovered. In addition with the recommendation of a second dose the number of doses delivered per year has almost certainly increased.
The contracted cost to the US CDC for Proquad (MMRV) is $8.57/dose (at which Merck is undoubtedly making a profit) and Merck charges $13.93/dose on the open market (additional 62% margin).
To put it another way, even if a person believed that there was only a 1% chance that there was a 1% increase in risk of Autism due to the vaccine, that would still be significantly more risk than death from measles. Although epidemiology is a science, vaccine sales are a business, and it is not unreasonable to weigh pharma's economic interests in vaccines that scale to the degree that MMR does. Pharma is not in general a philanthropic endeavor and a healthy skepticism regarding their products is not unreasonable.