Overthrown implies a zero sum of land, etc. How relevant is IBM to modern computing? Sure, they're doing some great work in supercomputing, but there's no monopoly they control like they once did. MSFT has a solid monopoly, but their relevance is lessening though still influential in some circles. Google is young/ambitious enough that it has its skunkworks projects - gGlasses is an extension from search, and self-driving cars is from maps/geo data, but it's still not really entirely defensible from their central data monopoly.