No you are wrong have a look here. There are many other uses than professional simulators. Have a look at this list
All those games would support a triple monitor span.
As for SLI yeah you are right, it is a poorly thought out architecture. Like with the TripleHead2Go that should sort of be build behind all this SLI stuff and then you'd be right.
This is why I get a single 8800GTX card with the matrox TH2Go
NVidia hasn't caught on to multi monitor gaming. Matrox has done so for a long time with their triple head graphics cards. Pitty those things are so slow.
I am hoping this revived post wakes someone up at NVidia.