I can be wrong about App Engine. Here is my reasoning...
I think App Engine does not fit nicely into Google's grand vision: which is mobile, social, and search for advertising purposes. So they need to be become profitable soon or they will be shut down.
However they lack enterprise customers and without enterprise and corporate customers it very hard to make things profitable.
This is wrong. AE is profitable. They have invested so much into AE. Every year at I/O since AE was launched, Google has been presenting the progress in AE. Many of the top companies today are using either AE or EC2 (or both). It is impossible for them to drop AE. They might consider moving away at some point, but in the next 5-10 years it is impossible. But the longer the service remains running, the harder it is for both Google and customers to move away. Eventually, if someone crazy, more competitive comes along, and when customers fall behind they will begin a deprecation and that deprecation period will be years long. When that does happen, Google is no longer attractive. Google will not profit anymore.
AppEngine and, really, all the "Cloud Platform" services from Google are a way to directly monetize the infrastructure that also supports Google's own applications. As such, if they are pricing them above the marginal hardware and support costs they are profitable, since the fixed costs are costs Google bears whether or not it offers them as an external service.
I think App Engine does not fit nicely into Google's grand vision: which is mobile, social, and search for advertising purposes. So they need to be become profitable soon or they will be shut down.
However they lack enterprise customers and without enterprise and corporate customers it very hard to make things profitable.