Though Orwell was writing about contemporary 1948 in "1984", many main stream SF authors saw a dystopian future were the world was ruled by a few mega-corps.
We have seen "consolidation" in food (all the companies making up Heinz-Kraft and Unilever and Nestlé), Chips (NXP and others eaten by Qualcomm, Altera and others by Intel, Softbank eating many, not juast ARM, Analog Devices & Linear Technology, Texas & Nat. Semi. Microchip & Atmel, and more), Hard Drives, OSes (we are down to 2 main and one niche desktop, 2 main and several niche servers, two mobile). Car & Truck makers, Aircraft makers. Credit card companies, Energy companies, Tobacco companies, Alcoholic Drinks Companies. Bananas etc.
TV sports Rights..
Big six paperback publishers (eBooks though are healty apart from Amazon's KDP Select & Prime distortion.
Ebay, Amazon, PayPal, Wikipedia, Facebook, Google almost monopolies in different areas. It seems the Internet has a positive feedback where instead of the envisaged diversity you get one operator per kind of thing.