If our eyes only saw frames (IE: 30 images a second), like a single lens reflex camera, we'd see images pop in and out of existance and that would really be annoying and not as advantagous to us in our three dimensional space and bodies.
In the Vienna of the second half of the 18th century, in addition to Haydn and Mozart, three symphonic composers, namely Leopold Hoffmann, Carl Ditters von Dittersdorf and J.B. Vanhal helped further the development of the symphony.
In the 18th century, the symphony was intensively developed, as Grove reports. For example, the Catalogue of 18th Century Symphonies lists more than 13,000 of them! At that time, every Court had its collection of symphonies.