I ran across this blog post recently from DreamHost.
DreamHost Blog » Build or Buy?
They talk about some of the reasons why you would want to "do it all yourself" and why you would want to outsource your operations.
Although the article is about the web hosting industry, it's easy to see how it can apply to the t-shirt industry.
Often times people want to know whether they should do all the printing themselves if they are starting a new clothing line. Or they want to know if they should get custom blank t-shirts made from factories instead of buying brands that are readily available wholesale. Since the "big brands" are doing it, they think that they should be doing it to.
The article gives some insight as to why that may not always be the best idea:
DreamHost Blog » Build or Buy?
Here's a snippety snippet:
 | Quote: |  | | | | | | | | | | As any fool can plainly see, the solution to the “build vs. buy question” has everything to do with quantity. The more you need, the more you need to build...
...But, even though it’s all just about quantity, “build vs. buy” is still an interesting topic! Because it’s really about how much quantity.
Google didn’t build their own data center when they only had indexed two sites.
Walmart didn’t own their own trucks when they only had two stores.
McDonald’s didn’t own their own potato farms when they only had two served | |  | |  | |
Read the full article here...
Article: build or buy (do it all yourself or outsource) t-shirts, printing, etc 
