In the last decade, Afghanistan became the source of most of the planets heroin. This happened largely because the previous supplier, tribes in the Golden Triangle (technically an area encompassing mountainous portions of Burma, China, Laos and Thailand), were forced to largely abandon heroin production. The two main heroin producers, the 50,000 Kokang (an ethnic Chinese group) and half a million Wa (a local group, with a language similar to Cambodian), came under pressure from the Chinese and Burmese (Myanmar) government. The Kokang, who have a lot of economic and family connections across the border in China (where another 40,000 Kokang live), gave in and halted nearly all heroin production. With the loss of heroin income (the Afghan dope was also cheaper, which played a large role in killing the market for the "Golden Triangle" product), the Kokang were more vulnerable to attack.
Recently, Burma sent the army into Kokang territory, and destroyed the 1,500 man Kokang militia. For decades, the Kokang had plenty of drug profits to buy weapons, hire lots of gunmen and bribe Burmese officials. No more, and most of the Kokang people appear to be fleeing into China. The Chinese government isn't happy with this, but at least Kokang is no longer a source of heroin, and other drugs, for southern China (where addiction and drug related crime was long a problem.)
The other two rebel groups near the Chinese border, the Wa and the Kachin (a large local tribe that was never into the drug trade in a big way), had a mutual defense (against Burma) agreement with the Kokang. But the Burmese offensive cleverly cut off the routes into Kokang territory, and forced thousands of Wa and Kachin gunmen to retreat.
Now the Wa are the next target for the Burmese army. The Wa are likely to be defeated and largely disarmed. This will end the heroin trade in the Golden Triangle. Well, at least the domination of the world market for heroin, which began in the 1950s, and ended only in the last decade, with the arrival of more government military pressure, and the growth of the cheaper Afghan product.
Afghan leaders know about the Golden Triangle history with heroin. The drugs (opium and heroin) made the drug gangs powerful enough, in their remote homelands, to resist military efforts to stop the trade. Even before heroin was invented in 1874 (via a chemical process that turned opium into the more powerful new drug), opium had been coming out of the Golden Triangle for centuries. But this was an expensive drug selling into pre-industrial cultures (where most people just got by). But as economies grew, worldwide, after World War II, opium and heroin addiction became a growing problem in the nations adjacent to the Golden Triangle. This gave rise to more and more vigorous efforts to shut down the drug trade.
Afghanistan is already suffering from a growing population of addicts, who tend to steal to support their habit. Similar addiction problems are growing in Pakistan and Iran. Afghanistan will have to deal with the heroin trade, or their neighbors will do it for them. What is now Afghanistan has been partitioned and pacified before, by empires based in Iran and Pakistan (and North India in general). It can happen again, if there is a great enough perceived need.