ART isn't about solving any social, cultural, or economic problems, IMO. The entire industry isn't about what is logical, ethical, easier, or possible (reference Nadya Sulemon and her situation).
Of course it would be "cheaper and less unhealthy" to hire a surrogate. The ART industry isn't about problem solving family building thru means other than ART. The industry is all about ART as the primary plan to solve family building when there is infertility.
The production of the CHILD is secondary emotionally for some individuals, to the primary goal of having the experience of being pregnant, and personally producing the child. Giving life. Being "the vessel". Passing on "my" DNA. Being essential in the formation of this new person. Etc. For some (ok, many) women, the ACT of becoming, and being pregnant, and giving birth (even high tech birth) is a strongly needed validation of their femininity. It is an important part of their view of themselves, and their self esteem. It is also a big aspect of culture and faith for some people.
The ART industry, IMO, isn't about creating children for the SAKE of the children, or for humankind, as much as it is about nurturing the psyche of those that they "help". JMO.
And ART is predominantly for (relatively) wealthy people in highly industrialized nations. It isn't a "need" for the continuing sake of mankind-- it's a "want". For me, it's in a category like purely elective cosmetic surgery, IMO. If you want it, and have it available where you live, and can afford it, you can have it.