“You believe that there is a necessity to go beyond the Shul Rabbi. Why?”
Most shul Rabbis aren’t poseks. They can answer a shailah that just results from a congregant not knowing the Mishnah Berurah well enough or something, but they can’t actually posken. There are also certain areas of expertise that not all rabbis have. For example, there could be an area in which there are hundreds of people with smichah, but only 1 or 2 are qualified to check bedika cloths (sorry for using that as an example, guys, but this is a common one). There are official, different levels of smichah as well, “shul rabbi” being the lowest. This isn’t anything invented by modern chareidim; this is a system that’s existed for centuries. Anyone who knows more about this than I, please weigh in.
As for your story with Rabbi X and such, you do understand that what you’ve described is a dynamic of the MO that the chareidi world is very critical of, right? What that system inevitably leads to is people thinking “if I’m just going to keep going to rabbis until the get the meikel answer I want, why not just cut out the middle man and be meikel without asking the shailah since the end result is the same?”
I think “gadol hador” is community specific. I don’t think there is such a thing as someone who can relate to all communities; it’s impossible. Even the names you mention like Reb Moshe are not true examples of this. He, for example, was not claiming to posken for chassidim and sphardim.