If you have universal devices Web cannot be blocked at all, you can install different browser or share websites via physical media, you can fit whole Wikipedia on SD Card. Same with overall computer networks, you can run a cable to your neighbor, unless you want to do it on a mass scale.
But I think you mean the Internet (please, don’t confuse Web and Internet), which is in fact very limited on ISPs side.
This is the difference. While with computers you can only censor what is done by them on public network (cables on the street, radio, etc.), with jail like iPhone you can also censor what is happening on the device itself. Those devices are dangerous and Apple made a big mistreatment for the world by creating iPhone like that.