Their own worst enemy?
I work in IT and like Linux, but I often wondered why other people just didn't seem to get it. Was the political and economic factors colouring my judgement of the useability of the system?
When I started my current job, I was forced to go back to using a Microsoft OS and apps desktop - I found it a big struggle. Slow, unreliable, difficult to move data between tools, hard to manage, poor ergonomics. There are some things I think MS does better - SMB makes a lot more sense than NFS for most purposes, mailmerge in OpenOffice is still painful. But compare OpenOffice's template system with that in MS Office, or try to fix a Microsoft window above others when switching betwen apps...
I recently bought a new laptop for my daughter (aged 10) - it came with Vista, so I thought I would try it out before wiping it. Gettnig the system installed (OEMs don't ship PCs with Vista pre-intalled - merely copied onto the hard disk with a bootstrap) took hours of effort (do you really want to run this program? HTF should I know what it does?). But I persevered and got a useable system set up.
My daughter is now pestering me to install Linux on it because its so much slower and flaky than the (also 10 year old) laptop it replaced running Linux.
I welcome the fact that she's got access to Apple Macs and MS Windows machines - I think there is tremendous value in being exposed to different tools when learning about computing - it enhances the learning of the computing rather than just learning your way around a single application.
Open Source is certainly no less useable/functional as the commercial alternatives. As far as I can make out, the issue is only one of market penetration/perception.
I would agree that, with no barriers to entry, there is a lot of badly written open-source software freely available - but this is irrelevant to what most people are actually using computers for.