We've all read of the kind-hearted publisher who recognized talent in a new writer and fostered it to the benefit of both parties, or of the Agent/Editor the famous writer thanks so fulsomely for their support and advice.
It possibly still happens.
For the rest of us, the truth is a little harsher. Publishers and Agents have cut staff numbers to remain solvent and the survivors are very busy. Glimpses of latent talent are not enough. They have to see something immediately marketable, or close enough to be turned into it with the small amounts of time they have available.
This means a clean edited manuscript without typos or corrections directed to the appropriate person in the organization and introduced with a professional query letter giving the required information in a recognizable format. (Familiarity saves time, gimmicks waste it)
The economies don't end there. Professional proof readers may still exist in large successful publishers producing mass market books. The others throw the responsibility back on the author. With print books there is the printer's proofs to help. The changed format highlights errors that slip under the radar on the computer screen because we've read the words so many times we "know" what's there. In E-books we don't have the benefit of that stage.
It all sounds a bit gloomy, doesn't it?
If it was easy, everyone would suceed and the intensity of the buzz produced by success would lessen.
Good Luck and keep writing.