Since they have been doing it for 15 years, they now presumably have structures and processes in place to keep up with sterilizing more dogs. They also had lots of volunteers helping. If this keeps going, it's probably manageable in the future.
The only sane, permanent solution is to police (prospective) animal owners or traders, who are the actual root cause of such mess. Why should everybody else compensate indefinitely for their lack of care and character?
If it's a step down from 100k, it's progress! Also, the numbers have been decreasing for a long time already, else Bhutan couldn't conclude that they are done.
I agree. Their numbers are either so low that it counts as "done", or they actually didn't encounter any for a certain amount of time. They must either continuously sterilize the small trickle of remaining strays or plan a follow-up campaign. Implementing low-cost tree registration of pets should also help.
