A Kickstarter can only generate more funds if either 1) it causes significantly more people to buy the product than otherwise would, or 2) it causes buyers to pay significantly more per copy than they otherwise would. It's not clear to me how either of those would work. Aside from those things, it just moves more of the sales up front instead of later on. Often it does that by offering a discount, which is counter to purpose #2. Also, it costs money to run, and Kickstarter takes part of the proceeds, so it's got to do so by a large margin to be a net gain at all. I don't see how that would have worked, even ignoring the question about who is doing the work.
Kickstarters consistently generate extra sales. First of all, Kickstarter is its own network. There are literally thousands of RPG players on there that just browse around, looking for projects to back. Second, it tends to inspire a heave-ho, let's do this vibe. So if you get all the existing fans to say, heck yeah, let's get a version with better art, you can get a lot of people to commit to purchasing, because there is both a perceived benefit, and a perceived sense of urgency. Third, Kickstarter campaigns catch a lot of eyeballs. They get shared around on social media, on forums, etc.
In the case of RPG projects, PDF sales have virtually no overhead, so structuring the price structure of the project to be mostly PDFs all but guarantees profitability. In the case of hard copies, you can right-size your print run to maximize your savings on printing costs.
But to me the first question is: why not more stock art? You would probably need a custom piece for the blue people and for the hawk people, but most of the stuff in these books is pretty generic. If cost is an issue, why not just get a Dean Spencer prescription, or pick up some of Eric Lofgren's not-quite-as-overused options? All you really need is a catchy piece of cover art; if you can't find something you like, that isn't already over-used, spend your budget on that.
I've seen plenty of books with smaller audiences with more investment in the art. Rolemaster is a classic game with an existing audience. I don't understand how it went to print with such an uneven, unprofessional appearance.