They certainly get more ad inventory to deliver when folks are zipping around ten small emails and clicking to read them. I'm surprised people haven't figured

They certainly get more ad inventory to deliver when folks are zipping around ten small emails and clicking to read them. I'm surprised people haven't figured this out. As we always say, if you're not paying, you're the product and not the customer. So of course Google wants to encourage lots of short emails. Google's incentive in designing the Gmail UI is to create lots of clicks and ad impressions. User satisfaction is secondary and held up mostly by "don't be evil". Google's only incentive is to keep it just tolerable enough that jumping ship isn't worthwhile. I'm sure Google does have many designers legitimately dedicated to improving the service. But also sure that they're closely monitoring the business moneymaking end as well.