Why would Samsung and Google do that, you ask? Well, the patent for these searches on a mobile device is held by Apple, and after the sales ban that the Galaxy Nexus went through recently because of it, Samsung doesn't want to take any chances.
It is a bit ironic to limit a search function in a mobile OS from a company whose bread-and-butter activity is search, but we are sure there will be ways around that, if not by 3rd party apps, then from the modding community. For now, if you accept the OTA update on your AT&T Galaxy S III, know that it will make your text search function rather crippled, but you'll still be able to search for apps, contacts and mail with your voice, which is not part of Apple's patent.
Thanks for the tip, Bryan!