Ablarc, as much as I typically love all of your posts, I have to let you know what my very first reaction to the first post here was:
"rubbish"
I live in Dorchester. Come visit Field's Corner with me. Let's get my inspection sticker done at the chop shop and talk to the garage flies that will start to pester you with all kinds of offers - for your car, and for your... person. I mentioned to one that I couldn't afford to fix the thing wrong with my car because I needed the money to buy a new laptop. No problem - this guy had three laptops "for sale" right there in the store.
We can play games like dice in the alley between the Vietnamese grocer and... the other Vietnamese grocer. The live chickens will be smelt and heard. The El rumbles overhead. At night the prostitutes walk the auto lots next to Dot Ave. Some of these ladies of the night are even female.
Then let's hit up Upham's Corner. Big, red brick former department stores, now populated with stores like "99 cents 4U". Again, the El rumbles overhead, and you can't walk one block without some kind of action - a catcall, an offer for goods or service. The sidewalks are literally teaming with people. Some friendly. Some not. Usually gathered in an inward circle, as if they are all looking down and studying the same brick. I once turned a corner and there's a guy in a pickup truck - selling frozen steaks. "They were extra from a fancy downtown restaurant". He was selling them for cheap.
These are not postcards from the past - this is any day of the week, in 2010, in Boston.
These are just the two neighborhoods that sandwich my little enclave in Savin Hill. Which admittedly, is quite gentrified and pretty boring. (Even the gay bar (d bar) sells $30 entrees and has a line of well-dressed heterosexual couples waiting for dinner)
But the grit exists. It's gone from what I typically refer to as "the urban core" of the city, as you very accurately describe - but it's alive and well on the fringes.
I can show you, let's get wings at Crazy Fried Chicken on Blue Hill Avenue near Mattapan. When they lost their "Kentucky Fried Chicken" franchise rights (one can only imagine why or how they lost it), they just spray-painted the word "Crazy" over where it once said "Kentucky". That's grit!