Ah, the poverty "ground level concrete porch." Yeah, we don't have enough money to build up so we can lord our wealth over our neighbors, so just pour the porch floor on the dirt....
The house I grew up in, and the house my Dad grew up in, and where Mom was living when she died, both had elevated porches.
The porch on the house I grew up in was only elevated maybe 2 feet, and when I was a kid the decking was in pretty bad shape in a couple of places, so in 1972 Mom and Dad pulled it all out and poured a new concrete front porch. That was a pretty monumental undertaking because the porch was 10 feet deep, 32 feet long across the front of the house, and turned the corner and went back along the side of the house for another 15 feet or so.
It was really nice because the porch didn't take a lot of sun during the day in summer because of the mature maple trees on the street (hence the name, Maple Avenue), so on hot days when we were sitting out there the concrete would still be fairly cool.
Mom's house had two elevated porches -- front and side. They were maybe 4 feet elevated. I rebuilt the side porch around 2014 because the under structure on the end (where the steps were) had started to go. The fir decking I pulled off (house was built in 1903) had ring structure so tight it was amazing. It was, for the most part, still in pretty good shape. By contrast, the pine decking I replaced it with had ring structure you could drive a car through. I triple primed those boards, and they still started rotting out within 2 years.
The reason houses in the east tended to have elevated porches (and the houses themselves were elevated above ground level)? Snow. It was an attempt to keep the wood above ground level to keep it from being rotted out by snow.
Oddly enough, though, many of the houses in the town where my Dad grew up had elevated porches made of... concrete. The one builder in town (late 1800/early 1900s) was really well known for building a series of brick piers and then pouring a concrete slab on top of them as the porch deck.