Yeah, I have no idea either why Microsoft would want to remove Message Analyzer completely, even if they could not maintain it. You can still download it through the Internet Archive:
Supposedly Microsoft is working on adding to the existing Windows Performance Analyzer (great GUI tool for ETW performance tracing) to display ETW packet captures, which will succeed Message Analyzer and Network Monitor: https://techcommunity.microsoft.com/t5/networking-blog/intro...
* 32-bit x86: https://web.archive.org/web/20191104120802/https://download....
* 64-bit x86: https://web.archive.org/web/20190420141924/http://download.m...
(those links via: https://www.reddit.com/r/sysadmin/comments/e4qocq/microsoft_... )
Or use the even older Microsoft utility Network Monitor, which is still available on Microsoft's website: https://www.microsoft.com/en-us/download/details.aspx?id=486...
Supposedly Microsoft is working on adding to the existing Windows Performance Analyzer (great GUI tool for ETW performance tracing) to display ETW packet captures, which will succeed Message Analyzer and Network Monitor: https://techcommunity.microsoft.com/t5/networking-blog/intro...