>I mean, there was no way he was going to drop $22 billion dollars on something and not get a return.

There's plenty of valid business reasons to spend money on ventures that aren't "net present value of cash flow projections exceed costs". There can be indirect effects like maintaining a moat - buying WhatsApp can be worthwhile simply to ensure that other companies can't use it to compete with Facebook's core business. Or there can be real option considerations. Or it can drive down the price of the complements of your core product.