I can answer you.
Simply as it is.
Bhagavad Geeta do promotes Detachement from the fruits of your job.
Capitalism of the West, which is poisoning India, is promoting exactly the opposite.
To know more about Why Western system is wrong, consider please to read another of my answer to a question related to Yog practices.
In that I mention how Devolved, Downgraded and Failed is a system which is Not spiritual at all and only believes in God of the Money Banks.
Suggested readings: Manu Smrtris [The Laws books of Manu]
Consider also Michael Cremo books or Conferences [he did a famous Conference for Google Company] about the human Devolution and how the Vedas are The Perfect books for the system of all the societies and how Vedas but also Smrtris and some Puranas, do explained that human beings did Devolved, not evolved.
Varna system was different than casteism.
Leave out any dramatic leftist political ploy and be sincere: capitalism is equal to more sorrows.
Varna Dharma is NOT to be confused with English casteism. That last is the Failure in India.
Read also the book "Brainwashed Republic" to know more about it.
About your : "It is a common belief that nepotism and similar practices lead to the lowering of efficiency and are not ideal for Darwinism—and by extension capitalism, which is by far the most successful socio-economic model we have devised as a species. The best example can be given by the Indian political situation itself."
I truly wish that you live inside Europe to know how much you are wrong about being enthusiast on our [I am European] capitalistic model.
How Nehru definitely did ruined India educational system.
And why Khan Firoz Maino are NOT the solution to that is the obvious consequence of that very long process.
And about that:
I have not read (nor do I understand) the Sanskrit version of Gita. I have only read the above English version. My questions is whether any of the following situations are possible:
The English translation is extreme and conveys a false/misleading meaning.
My interpretations of the verses are wrong.
Lord Krishna said this for that time, place and circumstance.
Otherwise, can you provide an explanation for why Lord Krishna said something that directly harms his followers and a "dharmic" society?"
My dear, Bhagavad Geeta teachings are Immortals.
It is up to you to live in order to only satisfy your physical body or to content with the enough, living Detached and making more karma yoga.
Oh yes! Christian Anglicism did penetrated the Shastras, in order to win obedients masses.
My dear Indians, please, do not be "Wanna be Western".
Myself I am " Wanna be 6.000 years ago Indian".
Happy of that and I think that you will be happy too.
Sanataan Dharma Kee Jay
Capitalism is Adharmic. Krishna knows that very well and Europeans [far less rich in money than your fantasy or imagination do expect] know it well too.