Gmail came in with 1 GB storage and grouping emails as conversations. To me, both of these aspects were revolutionary, and other email providers shortly followed suit.
* 1GB storage in 2004 to 15GB storage 21 years later suggests that something vital has stalled. Every other storage metric (price of RAM per MB, price of hard drives per MB, price of cloud storage per MB) has improved 100 fold over the same time period[1,2].
1: https://ourworldindata.org/grapher/historical-cost-of-comput... 2: https://jcmit.net/memoryprice.htm
Which freemail service isn't ad- or surveillance-supported?
> suggests that something vital has stalled
Why does it have to be a technology-driven limit? I dare say Google thinks that anyone with more than 15GB of email is a serious enough user to pay for it.
The original marketing was the the storage would grow forever, and you could believe it. Google was riding the an incredible high from smashing out what felt like constant Amazing New Things throughout the noughties. In fact, when they originally made the claim, back when Don't Be Evil was still the motto and they hadn't bought DoubleClick, I'm sure they believed it. By the time the final upgrade (or rather joining, of 5GB photos/Drive to 10GB mail) to 15GB came round in 2013, there was definitely a hint of the horns in the hairline.
Example: you can't create a new email label in the Android client. You have to log on to email in a browser and do it there. This was true when smartphones were a niche way of connecting to email, and it's still true today.