I'm very pro-adoption but the private adoption process in America is completely different to here. In the UK adoption is basically overseen by the government and involves the local council and assessments by a social worker, and also involves both birth parents (unless unknown or un-findable) having to sign off. As someone upthread pointed out, is a long and arduous process. British adoption is virtually always of older children, children adopted after being in foster care, or stepparent adoption. Newborn adoption (eg adoption agreement made while the birth mother is still pregnant) is extremely rare in the UK.
America has a private for-profit adoption industry, which is extremely murky. There is no government or social services oversight (in many states they don't even need to be licensed), it costs tens of thousands or hundreds of thousands of dollars, there's often little to no assessment to ensure the adoptive parents are suitable, and the process is much faster than in the UK. The majority of American private adoptions involve newborns. This obviously creates an ethical problem: if you're a private adoption broker and a wealthy couple has paid you $80k to find them a newborn, you have to go out and find a pregnant woman and convince her to give up her baby asap, or you have to give the money back. There have been many complaints about private adoption brokers agressively targeting vulnerable pregnant women, especially teenage girls (for example they actively target abortion clinics). Or targeting low-income/benefits/homeless/substance addicted pregnant women who might desperately want to keep their babies but are coerced via threats that their baby will be taken by social services, and wouldn't you rather your baby was adopted by nice rich people, than taken by social services and put into some horrible foster home? The pregnant women are often paid large sums, and told if they change their minds, they'll be sued and have to give all the money back.
It's just a completely different situation. In Britain, you're adopting a child who already exists and is in need of a family. In the USA, you might easily be adopting a baby where the mother is a teen girl who was coerced into not aborting, or a dodgy foreign trafficking situation. Basically anyone in the USA can adopt a baby pretty quickly if they have enough money.
Really good article:
https://time.com/6051811/private-adoption-america/