UPDATE 05/18/2019: David Burke, a Google employee, said in a Tweet that there is still hope for rolling screenshots. It's just that we may have to wait till Android R.
We've added scrollable screenshots to the hopper for Android R and hopefully can land it in that release. Make it so @dsandler 🙂
— Dave Burke (@davey_burke) May 17, 2019
One of the reasons Stock Android has few fans outside of hardcore enthusiasts is that it is woefully feature-starved. It isn't uncommon for Google to 'borrow' certain features that have been tried and tested by OEMs such as Samsung and Xiaomi. It is only a matter of time before Stock Android users start demanding that some features that are already present on other OEM's devices be baked into the OS.
While Google does its best to accommodate some of the features into a future release of Android—for example, Android Q is touted to ship with screen recording capabilities—users still have to rely on third-party apps to perform something as mundane as taking a scrolling screenshot. They're useful as they allow you to capture a conversation, webpage and other content that would otherwise require multiple screenshots in one image. It is especially useful for sharing long-winded conversations that would lose context if the file order was to be messed up.
A year ago, a user on the Google Product Forums suggested that the company allow users to take Scrolling Screenshots in a future Android release. Nothing came of the thread, until today, when an employee stated that it would be 'infeasible'. The employee doesn't state any reason, and it's anyone's guess as to why Google would think that way.
Other OEMs such as Samsung, Honor, OnePlus and Xiaomi have had a scrolling screenshot option for a long time now. Clearly, the technology exists and it's not like Google lacks the resources to give users what they want. There are third-party apps such as Long Shot that can do the trick, but users shouldn't have to rely on those until absolutely necessary. Maybe Google excluded it from Android Q because the OS is too far into development. Let's keep our fingers crossed for Android R. Or maybe Android S. It's hard to speculate, at this point.