I wish they'd do this. The whole magic of Minecon was that it's a physical event that you can attend. Now it's just another one of those streams that thousands of other developers do where they announce updates.
They are doing a physical convention again in 2020 called Minecraft Festival. It is exactly like Minecon however they just changed the name, it will be in Orlando Florida from September 25-27th. Here is a link to the website, https://www.minecraftfestival.com/
Question will be will it capture the magic Mojang and Minecraft had before it was purchased? There hasn't been any significate development that has enhanced minecraft experiences as much as it used too.
Biggest development has been Minecraft Earth. However, i don't see the lure of it.