They actually do feed fallen babies. That's why you're usually told to see if there's any birds nearby who could be a parent. More often than not, if the parents are not around, then that usually means they either abandoned the baby, or something happened that cause them to flee.

If the baby was laying down, and you were able to pick him up, then chances are, he had even less of a chance of surviving, if you went with the other two options. You tried your best though. It's hard, trying to raise feral babies. there's so many things to take into account, even moreso than with raising pet birds. It's just something you learn how to do, with experience.

There are different ways that aspiration can occur. If the windpipe is blocked, the baby will collapse and die on the spot because it isn't getting any air. If the formula has gone down into the lungs but there's not enough of it to cause immediate drowning, it can cause pneumonia. Your baby's death was too slow for the first type and too quick for the second type, so it probably wasn't aspiration that did it.

The parents might have had a second chick that they were taking care of because it was in a safer place than the one you found, or maybe the weather or general conditions were just too bad for them somehow. You did the best you could but it didn't work out, and life is just like that sometimes.

at the beginning he was totally fine, he would move away from me as I approached. He stopped doing it after being on his own for several hours in the heat (he was in the shade though) and when it was getting dark. He was just too lost by himself.

In general, I wonder if any chicks born on my front tree ever make it to adulthood. I don't see any fledglings learning to fly. Never.

You probably won't see them learning to fly, because flying out of the area is part of the process. Doves like to nest on my front and back porches, and I sometimes see fledglings sitting on the ground in the area. Once I opened the front door and scared one that was sitting on the doormat lol. But I don't see them after they take off flying. They go land in the brush somewhere, and the parents presumably find them but I don't see them again.

thank you for the help everyone

I wasn't talking about doves only. This is the first time I have doves nesting here. Last year it was robin family. I also have couple of cardinals eating here, so I am assuming they could have babies somewhere.
In general I mean that babies are usually seen when they leave the nest by observant people.

Not necessarily. Fledglings on the ground are vulnerable to predators so they'll be safer if they keep themselves out of open view, like under a bush or something.

we don't have any bushes or anything on the front. Just one huge tree.
That's why I was wondering about fledglings at all. I know we have some nests so apparently birds have babies here, but I wonder if this location is good enough to actually succeed with babies

I would like to get seed mix for wild birds around here but I don't know how to pick a good one. Any recommendations?
Also, do I need a bird feeder or putting seeds on the ground would be fine?