More amusing is that I/O is a conference of how to use Google services and platforms[0]. Really, look at it. It's almost entirely talks on how to build products for their p
platforms and pay-to-use APIs.
Presumably the developers still get their money's worth. If /when they don't soon or later these conferences will be full of empty chairs. So the question each person asks: "what do I gain by it," not what Google gains by it.