Dear Rainer Meier ,
100% agree with your comment , I do most of the time some IT help for the older people in the family , neighbours ,...
1)They find the windows 10 Mail app horrific compared to WLM 2012, ridicules big headers, contact integration,calender integration ,... just horrible
- The only program that doesn't work after the windows 10 update ("forced") for them is windows live mail 2012,this resulted in elderly people with no clue how to contact people, just one sad experience overall,...
For some I just repaired 2012 with IMAP settings, for others a desktop link to the online inbox. Which is not a ideal situation because some like you stated do read their mail offline which makes Thunderbird a alternative solution.
Just one side note , Google did something similar with Picasa recently , even removed the installer offline ("dick move")and only stating they should use Google Photos. Which does not even have a desktop application.
Conclusion Microsoft,Google,... sometimes they are so clueless and turn back in time with their services. I gave up on Google/Microsoft being logical with consumer based applications but can't go around them sadly.
Regards Ward.