It is indeed awesome. That being said let me introduce with a different set of thoughts.
Let's take jio for example: when it was launched it was VoLTE Plus IPv6 ready. So it was in a better position to offer it's services cheap.
The key take away from jio is that it is cheaper to plan ahead of time than to upgrade legacy hardware which was the case with author operators and they were playing catch up with jio
now apply this in macroscopic level with a country like India which has most of the infrastructure with non fibre medium to the end user while the core was always fibre from long time ( which you have pointed out when you said that they're being being powered by Indian transit providers in the backend)
But here comes the challenge to upgrade the existing infrastructure to the end user to fibre because nepal being young to the web is directly going with fiber and that is why they are able to connect villages with high speed internet and jump from 100 Mbps to 1 Gbps is not that difficult on fiber infrastructure, all you have to do is some upgrades to the backend while much of the setup to the end user remains the same with FTTH
plus please consider the fact that it is still the advertised speeds and ought to be different in real world usage ,
you can compare the quality of a AIRTEL connection with an exitel one as a example. Airtel will be some what superior service due to their uniformity on a Pan India basis; exitel is a hit or miss depending on the LCO
Plus I am sure BSNL FTTH has its services in some of the harshest of the the geographical locations in remotest parts of India
Coming to IPv6 penetration , I am sure jio and Airtel combined are serving more customers on wired connections then than the whole population of Nepal already.
Like I said nepal has the late movers' advantage in Internet