haifagirl, if Hashem decided that He will send Mashiach when there are (lets say) 100 Tefillos. Only 90 of them are able to be filled by people like the Chofetz Chaim and the Chazon Ish, and the remainder must come from “everyone else”, then your Tefillos accomplish just as much. Additionally, for the people you mentioned, who were involved with issues involving the public, they felt the need for Mashiach more. For someone who isnt, they need to “work harder” to feel the need for Mashiach. Your (seemingly) simple Tefilla will accomplish more than anyone can imagine, and never forget that no Tefilla is ever wasted.
About the original post, I once heard from a teacher of mine, that on Yom haChuppah, people ask for everything, but they tend to forget that davening for Mashiach includes it all.
There can be any number of reasons why Mashiach isnt here yet, but wanting him more, and davening more, will definitely help to bring him faster.