Answer: Was costly, time-consuming, sometimes inaccurate, and hard to come by.
Notated music is a reasonably recent development. Although some attempts to write music down were present throughout history, the first systematic use of a method that resembled ours, and that could be read by anyone is found around the 14th century. Before that date, even when music was written down using other less accurate systems, it was often limited in its reach because of the expense that writing things down represented. Therefore, it was mostly intended for use in churches, and even there, in a very restricted manner.