GREEK GENETIC CONTRIBUTION IN THE NORTH WESTERN INDIANS !
There is no doubt Ancient Indo-Greeks had been fully assimilated ---However their genetic contribution is very minimal and Uneven from North India to Afganistan --Hence the degree of their genetic penetration and its physical expression !
Please listen the last 3 minutes of the 11 minutes video and make your own judgement as i have no Historical or Genetic evidences to prove either way!
Absorbed, mixed with Indian stock like so many before and after them, naturalized. Sure, some might have returned to Iran and further to Greece (Although the remnants did not have much connection with Greece, they were in Bactria before being pushed out by Kushanas. They would be strangers in Greece).
They merged into the local populace. I won't go into the details as genetic discussions are banned but studies have shown a limited Greek presence in the population of NW Pakistan. Their most profound impact on the modern day inhabitants of this region has however been the headgear known aa Pakol. It developed from the Kausia and is a very common headgear to this day in Khyber Pakhtunkhwa and even in the northern parts of Punjab.