Hi /u/chikindiner,

I'm sorry this hasn't gotten an answer because it's actually a really great question. I will start off to say that I'm no expert on the development of orchestras--especially in Europe, but hopefully I can provide enough knowledge to help you get a good enough idea.

For Europe, orchestras developed in a couple of different ways. You have the development of orchestras in the courts as a way to strengthen cultural influence. These might have started as small orchestras but could have grown as a way to demonstrate more cultural influence (and also wealth!) Orchestras couldn't really be big in war-torn areas, so you see the first larger orchestras in more stable courts (such as Paris).

Another way they developed was through subscriptions from the elite in cities. (Funny enough, a lot of orchestras still run on some modified version of this model.) Basically, a bunch of people would pool enough money to hire an orchestra/conductor on the premise they would put on so many concerts. Public orchestras were a bit rarer, but they did pop up in places like London.

These orchestras at the beginning were often small. The development of the modern orchestra (like the ones that you are referring to) don't happen until you start seeing standardization of repertoire (and consequently, standardization of instrumentation to an extent.) Both orchestras you mention were actually created after the death of Beethoven, so they weren't great in disseminating new music in that sense. Really, Beethoven had a much bigger role in creating the modern day orchestra.

It's a lot trickier in America--the first orchestras were completely private amateur orchestras from immigrant populations. Eventually these coalesced into more public, but far from permanent orchestras. The first real orchestra/American conductor to get significant attention is the Theodore Thomas Orchestra--which was largely a travelling orchestra that would make stops in different cities. They eventually settled in Chicago in the 1890s, when the broader American public was more educated on classical music and standing orchestras could be supported. (There are a few orchestras that will mention earlier beginnings, but like I mentioned, they were really not the same kind of orchestra).

In America, the travelling orchestras especially were huge in disseminating music. Immigrants would have been bringing a lot of music over with them (and some European music, especially those of the "greats" made it over naturally). But for the average American, music was not a priority. Even in the late 19th-century, you only begin to see music as a profession--and the top students still traveled to Europe to complete their education.

Anyway, this is a very crude representation of what happened. If you're really interested in the development of the orchestra, it's very helpful to get a survey of music history from something like A History of Western Music. This is one of the major topics within this survey--but again, it's still a pretty crude representation of something that is so intrinsically tied with culture, socioeconomic and sociopolitical status. There's an intriguing collection of essays called American Orchestras in the Nineteenth Century edited by John Spitzer that would likely give you a more nuanced view into how the standing orchestras developed as well as the dissemination of music (for example, one of the chapters looks at concert programs in Boston).

If you're not in the mood of spending any money, I highly suggest taking a peek through some old Music Periodicals that you can usually find for free (and in full) via Google Books and other databases like The Musical Times (began in 1844).

I'm sorry I can't provide a more nuanced answer, but hopefully this satisfies your curiosity or gives you some directions to go in :)