Mike any one that has taken on your services is not a normal small business user of IT.
And it doesn't matter how many go over the whole system is wide open because of the of the millions that aren't going to change until there computers fall over.
So they may have there terminal solution but if the whole internet gets swamped they are stuffed.
If everything continues working with millions of XP OS's out there its just going mean even more people aren't going to bother next time either.