I can take my Android phone on any carrier and use tethering. I take my iPhone, and it randomly disables tethering depending on the carrier. Apple have also disabled downloads of apps and podcasts over 20 MB on the behest of a single carrier with a poor network (AT&T), applying the restriction to all phones, worldwide. My carrier doesn't care if I happen to download a 100 MB file, why would Apple ever want to restrict that?
Google only lets carriers screw with the phones the carriers themselves sell. Which IMHO is the prerogative of the carrier. If people don't want crapware, they don't buy phones from your carrier! Apple lets carriers screw with the feature set of all iPhones, regardless of where you bought it.