Yes. I develop on both Ubuntu and Windows.
I mostly do Node.js and Android development so I can work exclusively in Linux but some of my customers install my software on Windows. Always good to see whether everything works on Windows.
Yes. I can iterate quickly. If the end product is embedded, I port it to Linux once I’ve got the algorithms working.
Sadly yes. Too many apps still in old .net pre-core versions.
Noooo!
Dev desktop runs Ubuntu, MacBook Pro with OS X when on the road. Deploy everything as WebApps on hosted servers/services on both AWS and Google Cloud.
Before cloud hosting, I used to roll-in servers running HP-UX and AIX into clients' data centers. My support costs were a tiny fraction of those of my competitors using Windows server, etc.