Google has not been showing the metadata description for a while now. I guess Google is trying to test it on selected domains or something like that. The thing is that Google has too many factors for deciding the ranking of a page and meta description is only one factor. One reason for low ranking could be because of a poorly written meta description or a bad user experience. I am not fully sure, but I am guessing that is the reason Google is doing this. If you have any more info that is related to this, do let me know.
SEO is an increasingly confusing and complicated space, but there are a few rules of thumb that you can follow to make sure your site's on the right track. Leading SEO companies outline two main points that are absolute no-nos: