I don't know, as far as i know a pakistani never reached the top 100, sho why should you be the first player to achieve that?
It's just my opponion
Have you considered the possibility that few Pakistanis have even attempted to become professional tennis players? I'm guessing that we're dealing with a small sample size.
The history of a country of producing top 100 players is not reason, by itself, for one to give up hope of becoming a good pro. For example, how many top 100 players has Thailand produced? How many has Luxembourg produced? How many has Cyprus produced? It's a good thing that Paradorn Srichaphan, Danai Udomchoke, Giles Muller, and Marcos Baghdatis didn't quit simply because of the track record of their countries of producing top pros.
That said, the odds are stacked against a player from ANY country of becoming a top 100 pro. But that doesn't mean that you shouldn't pursue it if you and other knowledgeable people around you think you have talent that is worth developing.