What does this phrase ' keep overall company revenue lines climbing steep slopes' mean in the following context.
'Dramatic and Consistent Top-Line Growth
When organic growth may be hard to come by, acquisitions can keep overall company revenue lines climbing steep slopes. An existing concept comes to its new owner with all its tangible and intangible value — from units and equipment to menus and brand — as well as its customer base with it. Combined, these new additions to the original portfolio accelerate revenue growth.'