I'd love to hear your suggestion for a replacement. Any ideas where I can get an open OS that does exactly what I want it to while being absolutely sure that my personal activity is not being recorded or monitored in some way (either by vendor or virus)? Is there any OS where I can copy my $HOME directory to a newly-installed system and have all my applications behave in the same way they did on my old one? Other than OSX (which happens to get many benefits from open source tools which compile on it), is there another OS where anything you feasibly want to do with your computer is a Google search away? How about updating every single application on my computer to the latest version with a single command? Those are just a few of the things I appreciate about Linux without even mentioning its cost.
Linux has many inconveniences that have been gradually disappearing. On the other hand, the benefits that it offers are something that I have no hope of getting from a proprietary solution. I've only been using it for less than a year and a half, and I'm finding that my day-to-day usage has become more efficient than my Windows experience by leaps and bounds. I admit that I occasionally become frustrated by certain activities (wireless networking and suspend/hibernation routines come to mind), but even things like this are getting easier thanks to not-yet-1.0 software like NetworkManager.
I seriously expect that within a few more years, Linux will be no harder to use than any other OS out there, with the added benefit of it being more free and flexible than any other option. Problem solved.
On another note, if (as a service provider) you came back to me with that proposition, that would be a surefire way to lose a customer. I postulate that the average Linux customer would be more helpful to you than the average Windows or even Mac customer, as I would expect a higher level of technical savvy (less frivolous calls/e-mails to customer service) and a higher likelihood to file legitimate bug reports. If you are chasing these people away, you are losing on more than one count.