I think Google was the best destination for Sparrow simply because sparrow was created for Gmail. If Apple acquired it then it's focus would be iCloud email which is garbage.
Where are the small companies that are building for sustainment? All of these product disappearances do have a long-term effect of causing users to hesitate before signing up to use your offering.
Can't build much sustainment if you have to sell your flag ship product fur $9.99.
I agree iCloud mail is garbage, but frankly so is Gmail.
The sentiment that it would be better if Apple had bought it, I think, is more of a wish that some of Sparrow's awesome would rub off on the standard iOS mail client, since it is a similar app for the same platform.