Re: you pay 7 bucks for a coffee?
If you refuse to learn, test, and re-test yes the cost wills bite back in your ass and rip it off.
A competent migration will look at these issues and if required keep a number of workstations running windows, or wine, or VMs or whatever is required to keep the business working.
Linux is not Windows, if you have to learn anything at all that is the most important thing you are going to learn.
If you insist on Linux being 1:1 with Windows you are in for disappointment and failure, it does not work like that.
Linux is in what "I call the creeping in" phase, it is steadily replacing boxes here and there, first is an email relay, then is a proxy, the terminal server (text terminal server), the router is running Linux, minor databases are running now on MySQL/Postgress, random appliance runs Linux (or BSD), etc.
It is a matter of time...