I mean, yes, I and many others have thought of that.

To counter, have you realized HIV is an evolutionary entity that is optimized to continue existing by not fucking dying. HIV mutates like crazy. I mean there are other things like the flu that mutate, but because we have partial immunity to the flu we can use that immunity to create new vaccines every year against it.

It doesn't take much self research to see that HIV is a rather insane virus, and if somehow out of the gate it would have been wildly contagious that it could have wiped humanity.