Well, I funnily enough also agree with you, having just one widely used browser engine for all platforms sounds great in theory… (Until someone decides to not let you block advertisement anymore…;-))
Docker is one of the reasons I use Linux and for all practical purposes nearly all open source software is developed for Linux and later ported to the BSDs (if one is lucky) - so, again, I am also using Linux because it runs what I need to run.
I simply would love to have some practical and relevant options for OSS operating systems. I fully understand that this is not going to happen and Linux won.
Anyway, have a good day!