DR Freddie, I think you asked me this question before. My publisher has no money for promotion or publicity. The reason I spent two years trying to get a literary agent was because I wanted to get the book seen by major publishers with money. After two years and over 140 rejections, some kind and positive or constructive, but most of them a form letter "thank you for your submission but . . ." I went woth Robert Armin because he had published Paul Ford's memoir - and condensed a sprawling 1000 page ramble into a more manageable 250+ pages - and he was willing to take it on. I was also hoping an agent might lead to other writing work, but after my experience, I think most literary agents are unimaginative frauds. A lot of the agencies use the same submission form, and what was the book: humor? serious fiction? sci fi-fantasy? biography? young adult? I honestly think that today no agent would take Mark Twain, Thorne Smith, Patrick Dennis, Jean Kerr, James Thurber, oe EB White as a client.
There are maybe twenty-thirty of them I would say are good. My favorite agent rejection said "I don't know how to sell this book to a publisher but please send me the next thing you write."