RE reckoned they couldn't get a 500 single through the latest round of emissions controls. I suspect that means they couldn't do it for an acceptable price when they can carry on churning out loads of 350s, which are what sell by the truckload in India and ARE easier to get through the legislative hoops. Trying to persuade Sid to go back to producing a 500 single when the 650 twins seem to be doing well might be a fruitless task.
A.
I never saw any evidence that anyone from Royal Enfield corporate ever said this. What I saw was various media sources, speculating they COULDN'T, after RE announced they WOULDN'T do what was necessary to bring the 500 into compliance with BS 6.
We all know that emissions standards are not based on engine size, but are absolute limits of unit mass of pollutant per vehicle unit of distance.
I very much suspect that RE COULD have, but chose not to do the development work on the 500, as the 500 UCE had very poor sales in India, and poor sales internationally, especially after the 650s were announced.
In a very similar situation, Harley continues to sell their large 1750cc+ air cooled twins in the Euro market, but withdrew the Sportster 1200 and 883. HD never said they "COULDN'T", bring these into compliance, but this is the phrase chosen by most folks discussing the situation. HD, like RE, chooses to say nothing, and let people think that the mean old gov't bureaucrats are to blame. I think it's the accountants.
If you can point to some evidence, where somebody from RE corporate stated that the 500 UCE COULDN'T be brought into BS6 compliance, I'll gladly eat my words.