Why do more backpackers seem to go to Southeast Asia than India or China?

There's something I keep seeing in travel blogs that I'm getting sick of seeing. All these travel blogs encourage people to go "off the beaten path" or "off the major tourist trail."

And then, I look at their posts, and it's a big load of Southeast Asia this, Southeast Asia that. They never seem to go to the bigger countries like India, China, Russia, or any of those places, it's always Southeast Asia. I'm not saying southeast Asia is bad, but I am so sick of seeing travel blogs where 70% of it is Southeast Asia, maybe 20% is Europe or Latin America, then 10% is just criticizing Americans who don't travel much and wishing America had better public transport and a better backpacker infrastructure in general.

I get that Southeast Asia has a well established backpacker infrastructure and plenty of opportunities to get off the beaten path, but why don't more people go to India, Russia, or China, or even big trips across the US?

Russia is adventurous but has beautiful places like Lake Baikal, India is stressful and crowded but has many wonderful sights and great food, China has a tremendous variety of cultures and natural scenery, and the US...yes it's supposedly best with a car but people can backpack it if they plan carefully enough and don't mind using greyhound buses or slow Amtrak trains.

So what do you guys think? Do you agree with me that more people need to look beyond Southeast Asia?