Cracked, Tipping, and Falling Retaining Walls - Funny?

For the longest time, I noticed that there's a street with cracked and tipping retaining walls in front of every house. Considering that most of the walls are only about 3' tall, I'm not really worried about them tipping on me. It's more of a peculiarity and kind of funny thing because they all appear to be failing in a similar manner.

Tipping Forward and a Big Crack?
Below are some pictures I took a while back of just some of the retaining walls that were looking a bit unhealthy. If you look closely, it seems like they are all tipping forward with a giant crack between the front of the wall and the adjacent sides. Almost like the front is trying to pull away and the sides where they're connected don't want to let go, but aren't strong enough to hold on.

Tipping Retaining Walls

What's going on?
I don't know and I'm not a professional engineer, so can't say or give any sort of explanation that may be construed as professional advice...

Using common sense, why is the wall there? To keep back the soil that would otherwise spill or fall down? You mean something's pushing outward on the wall? Maybe. What's keeping the wall from being pushed out? What would happen if you put that wall on wheels? What would happen if you took away the wheels and anchored the wall down or just let it sit flat on the ground?

You tell me.

Armor Stone?
Those used to be some pretty well put together and nice looking walls. I'd be pretty annoyed to see them fail like that on their way out. On the same street, I noticed that some houses used armor stone in place of brick, concrete, and masonry.

Armor stone is a much cruder look, but I think it's also more attractive because it looks more natural. And in case you need a reminder on what they are, armor stones are just cuts of stone. From what I've seen, they're not usually polished and have pretty rough edges. Ask Mr. Google for more info.

Those walls seemed relatively newer to be honest, but some still looked like they had a big gap between the front stones and the side wall stones. Did they look as bad? I don't think so. They didn't appear to be joined together, so nothing seemed to actually crack. It just looked like the front stones got pushed forward a bit. Whether that's legal, safe, and structurally adequate is up to the engineer or company that put the stones in. Overall, I think armor stone is attractive for use as retaining walls and maybe they won't look as bad if/when they start going.