A bad photo is still a bad photo, and RAW will not change bad to good. What RAW will do, however, is retain all subtle detail and every bit of digital information contained in the original image, which gives you more to work with in post processing. The resulting jpeg you would then produce will be that much better. It would be just about impossible to send you a digital image to compare a camera-produced jpeg to a post-processed RAW to jpeg that would mean anything, for this reason: the inherent low resolution of computer monitors. I've spent my entire career producing images for offset printing (magazines, posters, catalogues, trade show displays, etc.). In that world, we deal in PPI (pixels per inch). Quality offset printing requires a minimum image resolution 300 PPI at actual reproduction size. On an inexpensive monitor, you are viewing an image at as low as roughly 60 PPI. Even the highest quality 4K monitors are capable of only roughly 160 PPI. Thus, if your ultimate goal is offset print reproduction, or a sizeable enlargement to a photographic print, your monitor is simply not capable of showing you exactly what the final output will look like. Side-by-side comparison between two jpegs would reveal very little difference.
Over my career, countless times I've had clients send me small, low-resolution images (72 PPI) they've produced and asked me to work with them and enlarge them substantially for print reproduction. I tell them they will be very unhappy with the results, which they don't want to hear. "But it looks great on my computer screen," they say. And that is true, because they're viewing them at maybe 80 or 90 PPI at best. At the required ultimate 300 PPI output, such an image will pixellate horribly and a great amount of detail will be lost. You cannot increase the resolution of any image beyond what it was originally created at. Photoshop tells you you can, but all you are doing in that case is making an image unnecessarily large. It will not increase the quality one bit.
I have also been told, but cannot confirm, that every time a jpeg file is opened and "saved as" another jpeg, even more compression is applied and more quality is lost. That is why the first thing I do if a client sends me a jpeg is to save it as a tiff or PS file, which are lossless formats. I then work in those formats for retouching and enhancement. Final files sent to a printer are always tiffs. If the client requests a jpeg of the final, at least I know I have done all I can do to preserve as much quality as possible.
Bottom line: if you typically view your images on a monitor or even a television, or stick to relatively small photo prints, a jpeg file will work just fine, with the advantage of having a smaller file size. Don't change if that is working for you. If you're doing work for commercial printing, and/or huge enlargements, you need every possible pixel, detail and accuracy in the original that can be obtained; thus, my need to shoot in RAW.
Last but not least, many in-camera jpeg algorithms will also result in slight color shifts. For most images, that is not noticeable and not a worry. If I am working with a client that makes a blue product, however, and the blue shifts even slightly toward green, they are not going to be happy. Easier for me to start with an accurate original which saves me time in post processing.
I hope this lengthy diatribe is of some value.
