You could dismiss almost any company as "if all you're doing is building an X app...". It's a no-true-Scotsman argument.
Even setting that aside, not everything is or should be a land grab. It's notable that all the examples you provided — Amazon (at least, its initial online store product), Uber, Facebook — are all B2C plays and I don't think that's a coincidence.
Even setting that aside, not everything is or should be a land grab. It's notable that all the examples you provided — Amazon (at least, its initial online store product), Uber, Facebook — are all B2C plays and I don't think that's a coincidence.