Except it's not the point. The article points out that it's moving to mediated consumption of email instead of just a good interface on "here's all your email". There's no argument about cash flow in the article, and you'll have to actually demonstrate that they're moving in that monetization direction to assert it.
Meanwhile I'm not sure what a non-hyperbolic version of "buying a spot" would be, so you'll have to specify for me to respond to it.
>> and selling an advertising email slot guaranteed not to fall into the spam folder would be the dumbest move an email provider could possibly make.
> Explain your thinking here?
Google makes money if people choose to use their products. Since so many people already use Google products today, there is some lock in due to convenience (all my email is already in there, I have an Android phone at least until my contract renews, etc), but offering a spam filter that doesn't work as long as someone is willing to pay would be a death blow.
The Promotions tab contains advertising in email, but it's the advertising you signed up for. For some reason this blows people's minds, but people really do sign up for those email updates from businesses to see new products and deals. Having a way to organize those emails is not some sinister new advertising plot by google.
Not to mention that an offer by google to make sure spam bypasses the spam filter for only 1 cent per 1000 messages or whatever is kind of going to get noticed.