Adoption is a complex, messy and sometimes brutal system (I've been through it - am an adopter and also have a birth child). Social workers quote at you constantly that this is about providing parents for children, not children for parents - which is how it should be, but I've seen some pretty gratuitous trampling on the feelings of prospective adopters, including those for whom this is their last chance of parenthood.
I used to think that getting approved to adopt meant you had reached some universal bar of good personhood, but the reality is that it's a market in which local authorities are looking for parents for the kids they are responsible for. There are financial incentives to match local kids with their own list of approved adopters (this was true when I adopted 25 years ago, can't guarantee it's still true).
Ethnic matching was a strong factor 15 years ago, so we applied to adopt in another London borough (not where we lived) because we were the right ethnic mix for that area (black Caribbean/Irish).
To my surprise, having another child already was NOT necessarily a benefit; a lot of children are 'advertised' as needing a family with no other children, or only much older children. This is because many, if not most, adopted children have very complex needs that require high intensity parenting, and all the resources their parents can provide. (Tbh, on reflection this was true for my kids too, though they do really love each other.)
I think most adopters are people who have experienced infertility, though they are expected to wait at least a year after treat.entvto adopt, and to be able to demonstrate that they have truly moved on. The process puts a lot of emphasis on ensuring you understand the reality of adoption, and how different it is from birthing a biological child (and it is REALLY different). And it also places high value on being able to demonstrate how you have survived and sorted crises in the past - they don't want needy parents but resourceful, resilient ones. And above all ones who can thoughtfully navigate the realities of parenting someone else's child.
I hope I have shod some light on the process, OP, and why it just wouldn't work to I introduce 'deserving' as a criteria. I'll finish on a quick what if: how would you feel about bereaved parents, who had lost their only child? Surely nobody deserves a child to love more than them? Yet you can see how that would be a really bad idea, if they were still so consumed by grief that they could barely function, and were looking for a new child to just replicate the one they had lost? But a few years on, having done both couples and individual therapy, taken time out of family building to heal and explore the world, and having developed deep understanding of grief and loss, they might be brilliant adoptive parents to child who has experienced grief and loss.
Good adoption services are about matching individuals, not categories. Oh and finally finally, many infertile people drop out of adoption recruitment because they are required to use contraception. You can understand why they are asked to do this, but also why it feels like an impossible demand.