Huh ? No. People in China are not facing just DNS blocking. There's DPI going on there (not for everyone), and they're nating a lot of people.
And, in US, what if using some other thing than your ISP DNS server gets forbidden ?
Anyway, most of the people in America and in the world do not have a single clue about changing dnsservers... Heck, most of the times they do not even imagine that a website domain relates to an IP address.
As an example, HTTP uses the "Host:" header which contains the domain name of the website in question. Deep packet inspection could work by recognizing HTTP communication, inspecting the "Host:" header and simply dropping traffic to censored websites.
Anyway, most of the people in America and in the world do not have a single clue about changing dnsservers... Heck, most of the times they do not even imagine that a website domain relates to an IP address.