and made their way around to nearly every Asian nation, changing their culinary culture, except India.

This greatly overstates the spread of chopsticks. The use of chopsticks as the standard dining cutlery (alongside spoons) is restricted to the Sinosphere (China, Taiwan, Korea, Japan, Vietnam) and Chinese communities in SE Asia. While chopsticks are used in Turkic China, this is a relatively recent spread of the chopstick, in the 19th century.

Chopsticks are used in continental SE Asia beyond Vietnam, and in Nepal, but usually only as a special-purpose implement for noodle dishes (especially noodle soups). The standard cutlery is fork and spoon, with the fork being a relatively recent Western influence, and the ancient cutlery being spoon and fingers.

The rest of Asia uses fingers and spoon or knife and fork and spoon or fork and spoon, including South Asia (India, Tibet, Pakistan, Bangladesh), and also Indonesia, the Philippines, Kazakhstan, Turkmenistan, Kyrgyzstan , Tajikistan, Uzbekistan, Afghanistan, Iran, Iraq, Syria, the Gulf states, Yemen, Oman, Jordan, Israel, Lebanon, Turkey, Armenia, Georgia, Azerbaijan, and Russia if one considers Russia to be Asian (since most of it is in Asia). In other words, most of Asia, both in terms of population and area, doesn't commonly use chopsticks. Chopsticks are largely restricted to the Sinosphere, with some near neighbours using them for noodles. Indian non-use of chopsticks isn't mysterious; it's just the majority Asian response to chopsticks.