Yes, but it's a bit hard to get; even in countries that try to improve trans-care rather than reduce it.
There are just so many therapists; the waiting lists are sometimes simply closed because they stretch years.
For many people, these hormones mean the difference between a livable life and extreme dysphoria, depression and suicidality.
If they could get them on the regular way, they would. But the regular way is often full of problems. So some people have to fall back to just do it themself.
I even heard of doctors who do some medical checks under the counter to ensure everything is done as safe as possible (but aren't able to prescribe hormones themself without prior psychotherapeutical indication)
So; your point would be valid in theory, but unfortunately for many trans-people, it's the only way to get their possibly life-saving medication.
Well, that doesn't mean it's not done.
My sister had a few (more than 20 simultaneously) rats.
One rat got stuck with her tail in the cage, and the tail had to be amputated, or the rat would've died. There were a few complications during the operation, and the bill would have skyrocketed to more than 2k€. For a tiny rat.
Needless to say, my sister insisted the operation continue. Rat lived happily for another 18 months