Dinosaurs in general had very good vision, and most likely saw in color. So having interesting skin patterns is already quite likely based on that. Big theropods probably exhibited cryptic coloration to help hide their bulk from prey they were stalking, and many giant Ornithischians had visually impressive structures that were probably for display. These might have been brightly colored and used both for social reasons and to visually intimidate predators. The frills of ceratopsians, the plates of stegosaurs, and the crests of hadrosaurs especially come to mind here. Some of these probably also used cryptic coloration to hide, however: a one ton ankylosaur was preserved with evidence of this, despite its armor. But the very biggest dinosaurs, sauropods of above 40 tons, probably had no predators as adults and so no need to hide. The thing is, even here, they may have been more colorful than elephants are. Elephants are the size of a lioness when born (about 200 pounds or 100 kg) and are intensively cared for by a network of female relatives—a mother certainly, but often a grandmother as well, and always several aunts and older sisters and cousins. On occasion an older brother will be around, too, and when there’s an older bull in the vicinity, he will be the first responder to a predator. Sauropods, though, are less intelligent than elephants by a long shot, as reptiles they lack such social intricacies, and are born much, much smaller because they hatch from eggs. Baby sauropods also probably did not get much parental care. So unlike the near-unkillable adults, baby sauropods probably needed camouflage. Now, animals do change skin patterns as they grow up, but I would not be surprised if sauropods kept some form of skin pattern as they grew up, especially as hiding would probably be an important defensive tool for many years and at much larger sizes than it is for mammals.
There is another question who answered this from the gorilla perspective. I am losely paraphrasing it (and on my phone do too lazy to link it), but the average gorilla eats north of 15 kilos if food a day. Protein is not exclusive to meat, however it is much more readily found and more of it per gram in meat. (For example, you have to eat both rice and beans to have a complete protein from the meal, super foods like quinoa are a complete protein on its own). So protein shakes have their use. are they essential to gain muscle? Not at all if you are eating plenty of good, complete proteins a day. Are they essential to become a huge mr. Olympia? Yes, among other substances some of which are illicit. The animals that live the longest aren’t necessarily the slowest. Some just don’t need to be fast to stay safe. Animals like tortoises live long because they have constant protection. Unless an experienced raptor finds it, its pretty much safe to graze and soak in the sun. They don’t need to waste much energy. At least not like a hare or a deer would. Certain groups of animals only had the information to develop a trunk through millions of years and learned to use it, while the other animals did not have that information. Adaptation is real but is only a secondary force for small and medium changes. The extreme changes came from genetic planning.