I did not reject the change of family names by a few people but I don't think they are that large in number that made you notice them everywhere since 2007. I have noticed the outbreak of communication after 2005 that made Shresthas heard more than before. 

Shresthas were largest number of people in lists. For example, just check the number of Shresthas registered in NEA or  any other professional lists and compare the numbers with others. The number keeps growing, I believe. Only few of them would be actually from those who have changed their family names.