It has long been the case that very cheap means of self-publishing, distribution, and information dispersal have crushed the corporate stranglehold on the generation of music prevalent in the 20th century.
That being said, the blurring of the definition of "instrument" has made the first part of that question somewhat more difficult to answer, especially as some of the more noted composers are AI entities who generally go without particular embodiments. Rather, while the most popular musicians are well versed in various accessories to their selves that allow for more interesting musical constructions, whether these accessories would be considered instruments today is a matter of semantic pedantry. Likewise, there is the gap between knowledge of use of an instrument and use of that instrument in popular music. These factors combine to render any answer to the first part of this question as markedly ambiguous.