Entertainers have always been available to the lower classes as well in certain cultures. Plays and other performances were around in ancient Greece and Rome for the general public at festivals thrown by the leaders to either celebrate an occasion, religious day, or distract the people from something going on. Throughout the middle ages, street performers would perform dances, songs, puppet shows, and little plays (usually with some religious undertone or moral message) in the town square (basically modern busking).

You are correct however, that wealthy individuals could have jesters, or bards in their service who would entertain them and their guests.

In terms of why we flock to entertainers and treat them like royalty, that's more of an anthro question.