Pire,
I am no economist, but have some idea.
you are right at present investing 40 million for 5, 40,000/y seems unrealistic. from bank you can get  40 lakh per year ( asuming 10% interest).

but point to be noted is

1. My natedars are living abroad so they have rented house at discounted rate (one can easily get 60,000/m) I know even this is lower than then what banks are offering these days.
2. Say in 10 years time because of devaluation and artificial prelevation of real stte and other things what will be the real value of toe money
3. In our childhood 10 million used to be very very big money but now that money is just good enougfh to buy a house, But that wont happen if you buy a house rent will increase every year ( house is in city center so in no time you can change tenant )
4. According to my natedar the he is increasing the rent every two years by 10% for last 10 years.
5. No one manages the house, tenant dont want to leave because the house is in safe place, near hospitals, schools, tempals, playground, police center.
6. 24 hrs transportation is available just outside of the house
7.According to my natedar the base is very solid ( he has blue print and record of iron used) so three more floors can be easily added) which will increase the rent or those floors can be used for personal purpose
8. Because of political situation in nepal it looks like ( i am not sure) the rupiya will be devaluated so the currency will lose its value but not the house in the city center.

I personally dont know why ppl are interested in ktm, there will be more attraction in state capitals later on but for new Nepalese ( who became reach overnight) can spend 4 karod, live in nice commercial place, with good source of income getting rid of all hassels

May be these points will attract propspective  buyers

thanks for the curiosity though