When goods are for sale

Forgive me and stop reading if I have already talked about this but I am still sort of shocked - though I imagine a similar situation exists all throughout South America...

In many places in the world you will find clusters of stores or market stalls that all sell the same goods.

From what I know there are there main reasons for this: 

A) trade guilds formed to maintain quality standards and higher prices for work.

B) towns/cities developed and people looked for certain good in certain areas of town (example: hey I need shoes- I will go to the shoe area).

C) royalty/powerful etc. wanted to control the resources/ sources of goods usually for tax or technological advantage.

Somehow much of the world still uses this strategy - the advantage seems to go to the consumer who can comparison shop (actual free market competition!) 

Bogota and Medellin have it to a degree that I find shocking... It's literally block by block of the same products. 

Here's an example from my few hours today.

I get off the metroline in down town. I look in front of me from the exit and see two stands of hats (baseball hats). I look further down the street and see 3 more stands of them. I look to the nearest store fronts (hats). Across the street 3 more stores of hats.  

I walk through this section into a park. I step inside to hear some prayers at the church... I walk across a bridge and down into a new block- paint. Wall paint, car paint, motorcycle paint, stores that sell paint, autoshops that do paint jobs...

I turn the corner and the next block over is auto parts, auto mechanic shops etc.

I walk down the block, it changes, at first I can't name it. Then I realize I am in party city. I don't mean that there is a party going on, I mean it is two blocks of mardigras beads, streamers, party hats, plastic trinkets, holiday fare... 2 blocks of stores that are all party city(the store).

I cross back into the hats zone, more further clothes and shoes. Block after block of shoe stores all pretty much selling the same style.  Interchanges with clothing stores that all sell the normal stuff.

A few blocks and suddenly the clothing style changes. Now it's more like club clothes. 

I am cued to the change when a group of vendors start whistling at 2 women who are a little more scanttily clad. The whistles continue as they walk through the market stalls that take up the street. It's like the guys are sending an alarm call more than flirting... But suddenly all  of the women in the area are wearing clothes that you would typically only see in a night club. This includes the vendors selling the night club clothes. 

I look at the mannequins and laugh. I can only describe them as pornstar mannequins. I see two older women pointing and laughing at the mannequins  too, but for the next 3-4 blocks it's these more scandalous clothes and scandalous mannequins.

The next section is clothes meant for teens, less scandalous but still not school wear.  

I finally get out of the heavy traffic area and into open streets, the new section is a mix of school supplies and office supplies. Strangely enough some tools and basic matenaince stuff is thrown in. 

At this point I am walking away from down town, and into a neighborhood that is a little more rough. The area is full of trucks, dropping off supplies.

I see a series of warehouse fronts that have wood and wood panels. 

..........,..,,,,.............................

I've asked a few people about this system. If it is zoned intentionally or just out of habit. The smaller towns don't seen to have the exact same problem but many of them do sell the same goods just less variety in the small towns.

The suburb of Medellin that I am in doesn't have the same layout. But Bogota had it to a degree that was hilarious. One whole block was Mexican mariachi instruments/costumes and bands for hire. 

....................................................

On a completely separate note:

MY FIRST SOUTH AMERICAN COCKROACH!!