Some (many?) words attributed to Shakespeare follow the ordinary processes for making new words in certain open categories in English, and so you could argue that anybody might make these words as a competent English user, grasping for this specific meaning, has available the tools to make this word for that meaning. This could happen completely independently, even many times. If you need "invulnerable" or "majestic" for example you don't require the services of some specialist word inventor to come up with them, you can just make those yourself since you're a competent user and there are rules.

But Shakespeare used them in a context which people remembered, so that's why it matters, and in the process Shakespeare gets to choose some parameters for these words which are not set by the rules such as their emotional valence - is this a good thing or a bad thing? The rules usually don't dictate that, but usage does and Shakespeare can set the trend.