Excellent question, and excellent points...
The short answer is: Whether this Kickstarter succeeds or fails, I am making this game. The only things that the Kickstarter will change are the timeline, the amount of content that will be included, and the amount of time spent on the content. It will also make it clear, to Tim, that this is something that his fans support him spending a considerable amount of his time on. If the Kickstarter fails, it will be mostly the same under the hood, but will not have nearly as much content, and will take a few years to make instead of one. The $500k actually seems high to me, too, and I chose that amount. But it's the amount that allows me to say, with absolute certainty, that this game will be completed as described, on time, and with a level of quality and refinement in keeping with that funding amount.
More details:
No, I'm not well-off enough to survive for a year with no income - if I could, I absolutely would. Without going into detail, I might be able to go a month, and not because I'm irresponsible with my money. I've got 4 kids, and a good paycheck but... 4 kids. It's not personal risk I'm avoiding, it's risk to them. I'm going to be taking a pay cut, but not so drastically that I risk leaving them destitute or homeless. And in exchange for that reduced "salary", I fully expect to be spending a minimum of 60 hours a week on the project, to further ensure that it's on time, on budget, and high-quality.
The biggest cost is actually "developer" time, only a fraction of which is going to be for programming. I've said in other responses that the coding is the least of the effort (a couple of months of full-time work), and working with the backers to develop the content is going to take up the bulk of the time. Part of this Kickstarter is the experience and the involvement with creating the game, and while it's going to be fun for me to work with all the backers, it's going to be extremely time-consuming. I can't shorten the schedule and still give the backers the attention and consideration they deserve. With significantly reduced backer involvement, the target would be half as much, but the game would have a lot less content as well.
I've also said repeatedly that everything raised by this Kickstarter will go toward game development. In the highly unlikely event that everything falls into place perfectly and the game is completed significantly ahead of schedule and the backers (as a group) don't come up with other things that should be added to the game, the backers will decide what to do with the surplus.
As for profiting from future sales... It would be great to make enough to continue doing this full-time after this game is finished, with the same level of quality and detail, but I don't expect to make much more than that. I've also made it clear (I hope) that I want to be as reasonable as possible with the pricing for future mods and such, so if I start making a lot, I'll drop the prices.