This weekend the 3G mysteriously stopped working on my iPhone, so after months of use, I rebooted it. Rebooting the iPhone takes 1+ minute, and there _is_ a kind of splash screen shown during that time. The reason it appears instantenous during normal use is that it doesn't actually boot or load, it just turns the display back on. Also, many iOS apps actually have splash screens, you just don't see them very often as they're usually already running in the background (big apps like Facebook, and even small ones like PCalc Lite or Quotes).
You can kind of achieve this with Windows + Adobe stuff too. Just don't quit Photoshop when you're done using it, and don't turn the computer off, put it to sleep. If you have an SSD (like your iPhone), then swapping Photoshop back into main memory will also be much faster.
Of course the OP is right, Adobe stuff is bloatware and sucks. Fortunately for non-pro designers, there are alternatives like Pixelmator and Paint.NET.