Now, making it production-quality, efficient, scalable, and the rest -- well, y'know. That's why people use cloud-based services in the first place.
But I think there's less fundamental lock-in than you think. Cloudinary, for example, will let you upload an image and get a tag out. ABBYY and OmniPage/Nuance and others offer cloud-based OCR.
I'm biased - I'm at Google this year - so take this with a grain of salt, but while I have the feeling that Google can do it better and more affordably than a small team could do it on their own, I don't think that Google pulling the API would leave people up a creek without a paddle.
Google's face/landmark/label/text/logo detection models are open source? Or there exist open source pretrained models?
The quality and size of the training set is (at least) as important as the machine learning tools. I imagine Google has access to a pretty big data set, along with the computing resources to process it.
Google's Inception v3 pre-trained image recognition model is open source: https://www.tensorflow.org/versions/r0.7/tutorials/image_rec...
That's the hard part because as you note this is computational intensive (the training data is actually open source as the ImageNet dataset)
There is existing code for the others part that perform pretty adequately (with the possible exception of landmark detection).
Eg:
Face detection: http://docs.opencv.org/master/d7/d8b/tutorial_py_face_detect...
Logo Detection: http://www.pyimagesearch.com/2015/01/26/multi-scale-template...
TensorFlow Serving: https://github.com/tensorflow/serving
ReCeption (actually they call in Inception v3. Not sure where I got the ReCeption name - though I'm sure I read it somewhere?): https://www.tensorflow.org/versions/r0.7/tutorials/image_rec...
Using a SVN on neural network extracted features: http://blog.christianperone.com/2015/08/convolutional-neural...
If you want a quick and dirty version here's some Python to create a web service that calls a Caffe based Image recognizer: https://gist.github.com/nlothian/c3519adb81b3452c1938
There is also http://www.deepdetect.com