Whilst your thesis is trivially true (there must be differences in products, otherwise we effectively have no choice), in a practical sense it leaves a lot to d

Whilst your thesis is trivially true (there must be differences in products, otherwise we effectively have no choice), in a practical sense it leaves a lot to desire. To have choice, the vast majority of functionality must be fungible between two different, competing products. If I have a Ford, and want to buy a new car, the new car can be used on the same roads, my driving experience can be transferred, I'll have access to the same fuel in the same service stations, I can park the car in the same places, etc. The two products are highly fungible, and where they are not, it's because they are being specifically targeted at a need that I have. I do not have to give up using roads, or the service station network just because I need a bigger car to hold my kids - the big cars are still designed to fit on the same roads. To use a computer example, I use Fedora at work, because our CPU manufacturer provides their tools (port of binutils etc) only for Fedora, and it's a major pain in the neck for me to deal with having to repackage them for my desktop of choice when the tools or my OS is updated. I would prefer to use Ubuntu, but I can't, because the two products are not sufficiently fungible, ie the market is fragmented, and I don't have a choice.