The reason is simple : our film industry is non existant.
We can criticise or troll Bollywood as much as we would like to. But the harsh reality is that the industry makes millions of dollars worldwide, and this is how Indian actors get international exposure and become superstars. Their film industry gives them the opportunity to become superstars.
Even if most of their films are bad, Bollywood in general is 100 times bigger and better than Lollywood, and it's a fact that people like SRK or Akshay Kumar are more popular in Pakistan than the majority of our drama actors.
In fact, just a few months ago, I read an article calling Shahrukh Khan the biggest film star of the world. I am pretty sure that he is more popular than the majority of Pakistani actors in Pakistan.
I am not a huge of fan of either, but being a Pakistani, if you ask me to choose and watch a Pakistani film starring an actor I don't even know and a Bollywood movie starring Aamir Khan, I will most probably go for the latter as well, and a lot of Pakistanis will do same.
You just have to look at it in this way: In India, their people will relate to a very small number of Pakistani legends such as NFAK, Atif Aslam or Fawad Khan. Only Fawad belongs to the film industry from this list, and Indians know him because of his work in Bollywood.
On the other hand, a huge part of Pakistani youngsters will know and recognise not only the likes of SRK, Salman or Aamir, but even some of their yesteryears' superstars such as Amitabh Bachchan as well.
This shows that the Pakistani film industry just about manages to have a limited kind of appeal on a national scale.
It really tells you a lot when we say that our serials are much better than our films.
The fact is that Bollywood has become so big from an economic point of view in the last few decades that their actors have become international stars.
Unfortunately, Pakistan's film industry being in the dumps, our talented actors just don't get the opportunity to showcase their acting skills, and find themselves in a situation where they have to fight for a chance to get a break in Bollywood, or to limit themselves to Pakistani serials for the biggest part of their careers.