Read the book, that's exactly what he's saying, and that way of thinking is a fundamental aspect of dialectical materialism. The semantic and conceptual differences come when these small changes accumulate and a new way of describing the phenomenon is necessary.
That's...not really true in any substantive sense. Capitalist imperialism co-developed with capitalism the whole time the latter was developing from pre-capitalist systems. The only way you can say either came later is if you artificially construct both as binary rather than continuous transitions and then draw the arbitrary binary line one each to make that ordering work.