Question

why did their ideas recede into the background of atomic thought until 17th century?

Answer 1

Most of the postulates of the modern atomic theory were first introduced by Leucippus and Democritus in the 17th century.

However, Aristotle, who was a prominent philosopher of that time, disagreed with their concepts. Also, the Catholic Church disagreed with the atomic notion that the universe was endless and that it was “not created by any outside power", which was against their notion that everything was created by God.

So, the concepts of their ideas receded into the background of atomic thought.