Lots of places are heavy Mac, even when they only develop server side software to run on Linux. The laptops are well behaved, low maintenance, have good UIs, and have good support.
Many people don't care about conferences at all, or their employers don't care (and hence these people don't feel like spending hundreds of bucks from their own pockets to attend), some don't want to go on conferences and so on. For/to many developers they are just irrelevant. Obviously not everyone goes to coffee shops, either.
Your experience can be different, but without a global survey, there's no way to be sure.
The closest proxy we can probably find is what CS students are using - as they'll likely continue using that platform going forward. There aren't hard reasons to switch as there used to be -- VPN software tends to work well on all 3 platforms, and there's not nearly as much client-side native development as there used to be.