People will always find a way to grow coca and trying to eradicate it will only use money. They will find a way to hide their crops, just as marijuana farmers have done. Some farms may be destroyed but they won't be able to destroy all of them and the crop will still grow.
Yes, coca production and consumption eradication efforts are doomed to failure, because there is a lot of profit that individual producers and even governments want to make from selling this drug. Cocaine is highly addictive, and producers will continue to feed on those addictions to make sales, even knowing that laws are very tough on cocaine producers.