Also for server security, vendor bloat is as much a problem for Linux as it was for Microsoft (since always). Microsoft went through decades[1] of ridicule which resulted into immense internal pressure to improve security.

When you compare major linux distros now (and look at the lkml or other open source communities) then Linux hasn't changed much since the 90ies. It's still full of people who are almost religious when it comes to accepting that just because a system is open source doesn't automatically make it more secure.

Monolothic kernel with containers? anyone who has the luxury of starting new (Like Linus in the 90ies) would point the finger and laugh. Some people laugh now, but nobody hears them because we already have this cool thing called linux so why would you re-invent the wheel ...? (so seems the logic towards anyone who questions the design) ... If you say Linux is less secure than Microsoft or Apple you must be a troll (is the answer to most who dare to say apple / microsoft are more secure than Linux)

[1] http://trustworthycomputing.com