You won't be educating your customers by saying things like "Country X cameras are junk, but Country Y cameras are awesome."
It's a stereotype.
As for who manufacturers surveillance cameras in the US, very few. The largest is likely Arecont Vision, and they have a terrible reputation for quality, but that says more about their company's culture than the US as a whole.
In general, cameras manufacturer by reputable, well known companies, typically are fairly reliable. The main differences comes in feature sets and manufacturer support.
The least reliable camera manufacturers are the no name shops selling cameras for a fraction of the going rate ($14 for an analog camera, $30 for an IP one, etc.). Those frequently have big quality problems. And most of those are based in China, but that's not because China is inherently bad, but because someone selling cameras at that price level, inherently has challenges in delivering a quality product.
Answering your questions:
2) Nowadays, it's hard to say as even the biggest American companies are buying from Asia as OEM putting their brand on it
3) From the best and most expensive, generally speaking:
1- Europe, mainly German and Italy
2 - Japan
3 - Korea
4 - Taiwan
5 - China
But what I've learned after ten years negotiating with Asian manufactures is that not all the cameras made in Japan are the best and not all the cameras made in China are worse than the others. As John said, it's a stereotype; you need to study the specs, ask for samples and test them. I really found good jewels in China at one third of Japanese price.
Some cameras are made in Canada also. Avigilon, Silent Witness to name a few. Not everything is in China.
It would appear that currently one can get both junk and reasonable quality cameras from China. I think that's more a statement about where China is on the manufacturing maturity curve this week. Not trying to offer a stereotype comment. P.s. I am pretty sure you can get junk cameras made in e.g. US, Sweden, Germany, etc. if you pick the correct crappy vendor. This is why we studiously read our ipvm.com emails, they do testing and testing is how you separate the junk from the non-junk...
[Note: Poster is an OEM]
Some of the Chinese manufacturers are outsourcing their cameras to third parties both in China and other emerging markets to save costs.
Whilst there is a lot of OEM going on from China into the West, bear in mind it's not always the same product on sale in China even if it's the same SKU.
The OEM product will potentially go through much more rigorous testing and likely a completely different production line than the local market product.
Components used may be of a higher specification/tolerance and not sourced from grey markets and guaranteed not recycled. Warranties offered may be longer.