The barriers to entry definitely exist, but is it the technology itself that creates them, or is it the intellectual property laws we've adopted? Capital is a barrier but it's far from an insurmountable one -- there's plenty of capital floating around in the world. As a thought experiment imagine what the tech industry might look like if the US introduced some form of compulsory licensing for software (for patents? for copyrighted source code?) like what exists for music.

Natural monopolies certainly exist in sectors of the economy like public utilities, but I don't think they are so strong in tech.