I agree that Google vanishing in an instant would have a more tangible short-term effect than Apple doing the same. But I feel you paint them as (nearly) opposite ends of a spectrum. Google provides many centralized services that people have come to depend on, whereas Apple creates physical products that would continue to function even if the company ceased to be. But Apple provides some similar centralized services and its various stores that sell virtual products (apps, music, video).
Either disappearing would be inconvenient for a lot of people—notably those who use centralized services—but my opinion is that in both cases, people would adapt fairly quickly.
All that said, as someone who doesn't use services or products provided by either of these two companies, my instinct is to agree with you that Google feels like it provides greater net value to society than Apple.