It takes time to build a business. I spent about 3 years detailing part time before I quit my day job. Those 3 years I basically spent learning to be a better detailer and I put all of my detailing profit into building my arsenal of tools, slowly starting to buy chemicals in bulk, and buying a van with all the equipment needed for mobile work. I made it a full time gig when I picked up my first dealer account. They called me out of the blue with a promise of 15-20 cars a month, even through the winter, all Audi/BMW/Benz. I made 100k my first year officially full-time in business. Sometimes I worked 7 days a week, 14 hour days but it didn't matter... it didn't even feel like work because I love it so much. If you have the passion, do quality work every time, and have systems in place to pull customers to you (website, google maps listing, FB page, etc.) eventually things will work out as planned.
That seems like the sensible and lower risk of the suggestions. building clients and skills while still bringing home steady income will most likely keep you from throwing back boxes of KD and hot dogs every night (If it wasn't so unhealthy, I wouldn't mind that). I am looking at starting a business, but I also have a family to feed. I'm trying to do some freebies for friends and family to help bolster my skill set and if I make some extra money from them, I can use that to build my arsenal of tools and products to do the job right, which it seems like you have everything you need. As far as "market saturation" goes, IMO if you take the time to create a brand that is clever and will appeal to todays technology, coupled with some good ol' fashioned face to face networking, things should start snowballing from there. No one (especially me) wants some grease ball anywhere near my car throwing on flyers, leaning up against my freshly polished paint at Walmart and scratching the, you know what, out of it with the zipper of their hoodie. I'm not calling YOU a grease ball, but I'm trying to convey to you how someone might feel when they see that stuff pinned under their wiper. It screams Low quality and screams someone just trying to squeeze more of my hard earned money out of me. I admire your hard work and determination and I wish you the best of luck my friend! Keep it glossy buddy!