Ever since the birth of the PC, you’ve taken a risk when you buy a new product. If it succeeds, it’ll be around for a long time. If it doesn’t, it will die. Google isn’t breaking any new ground here.
What’s different is that Google’s products are all cloud-based. When Google Reader goes away on July 1, that’s it. It’s gone. If it were an ordinary bit of software that I’d installed on my PC, this wouldn’t be a problem. It would keep on working for years even if it never got another update. I’d need to replace it eventually—because of an OS upgrade or a desire for new features that finally got too strong—but I’d probably have years to work that out.