Actually, you are generally correct (disregarding some minor technical misstatements). With any color process, the control was very strictly limited. Even Ansel Adams never resolved this issue and never did very much with color, because you really can't control it, and for certain, most of what you can do if you try is screw it up. For color print film, you can do some *very limited* control, but mostly all you can do it make the color be off. In the specific case of slide film there is virtually no control whatsoever possible. You can underexpose or overexpose it, but aside from that, forget it. Unless you get it scanned and use Photoshop.
Digital, as you note, more or less resolves that limitation for color, you actually can manipulated it to come out the way you envision with great ease. If you only ever use 35mm, digital has exceeded it in quality as well. For the vast majority of people, digital in the usual 2/3 frame or full-frame 35mm format is FAR, FAR better quality than an amateur could get with common processes and actual 35mm film. Crappy cell phone cameras with sensors the size of a few grains of rice usually do better, too. There's still nothing digital available to amateurs for sane money that can match larger-format film. and I expect that the 120 and 4x5 formats will outlast 35mm.
The wrong part is what happens when you take film to a lab - there were and are essentially *no* computer-based evaluation steps in slide processing. They run it through a fixed process (E-6 in this case, as noted elsewhere, or K-12 for Kodachrome) and it comes out however it comes out. There were some weird second exposures and some hand manipulation required for Kodachrome which is why there were only two processing facilities in the entire world for many years, and for the last 10 years, only one place to process it You live in Botswana and want your roll of Kodachrome 64 processed? It went to Dwayne's photo in Kansas.