We actually have personal helicopters but only the super rich can afford them. Landing space is limited, fuel is quite expensive, piloting is hard.

Now the trouble with those is mostly the space required to start and land these things. Think how skilled those firemen in the picture would have to be to operate even slow jetpacks or helicopters and not crash into one another as well as land reliably. Birds have an advantage of advanced evolved neutral circuitry to handle all this.

I'd say the main advantage of birds is small weight. If humans were as light as birds, personal flying machines would've become widespread long before computers. Would've been much safer too, because light creatures can endure falls from much greater height.