Absolutely true - with the rise in aftermarket accessories for vehicles, the manufacturers are trying to keep some of that money in-house. Once upon a time, factory radios were mostly single or double din square units that could easily be replaced. Heck, my first car (an Acura Integra) did not even have a radio - it was an option. Then eveyone started making proprietary radios and dash/consoles that could not readily be modified. Now with all the modern tech that needs to flow throughout a vehicle, it's almost impossible to personalize/customize a radio system in a new car...
I am sure with all the options LR has already laid out for the Defender (several models, and several "lifestyle" option packages) that they have a steel bumper with a winch that can be ordered. Whether or not third-party manufacturers, such as ARB, are being included so that they can make their own versions I am unsure. We'll know by how quickly they come up with an offering. If they have to wait, buy a Defender and then tool a bumper from a live example, then we know LR is definately focused on forcing them out as much as possible.
There is little doubt the Defender will require a special oil, non-standard windshield wipers, fluids that meet some new spec no one has ever heard of yet, and a host of other proprietary tidbits to keep people coming to dealers and/or buying maintenance products from them directly.