Aftermath of Black Lives Matter protest in Paris

The transcript discusses the importance of piggyback in the context of a project, emphasizing that none of the current progress would have been possible without it. It highlights the evolution over four years and compares the current state to a tool, like a screwdriver, that aids in achieving goals.

What does the speaker mean by 'piggyback' in this context?

How does the speaker compare the current situation to four years ago?