I don't think that most of Marx's analysis of capitalism falls flat in the face of modern developments; some of it of course do (such as his theorised 'Asiatic mode of production' which didn't exist) but for the most part I think a Marxian analysis is a cogent one, at least from what I've seen. Marx was in a good position to envisage how technology would develop, having seen the result of the industrial revolution himself. Marx intended for his analysis of capitalism to hold regardless of time frame; arguably, and indeed into the future beyond capitalism taking the form of the theory of historical materialism.