Oh, I know it's doable... it's just an issue of ease-of-use and a lot of people aren't up to using WINE to run the windows installer and transfer everything over to a Mac DOSBox.
And now, it looks like you don't have to... The 4 DOSBox-based tex games were included in the OS-X update earlier this month. Directly downloadable and useable now.
Thanks, GoG.
cogadh: It might be a huge market (very debatable), but GOG is a small company. They don't have the resources to dedicate to supporting multiple platforms at this time. In the past they have very clearly stated that they are not opposed to supporting other OSes, they just can't right now.
The market for Tex, per se, probably isn't huge. But the number of gamers who remember GoG games and have a mac now? I'd bet it's a pretty substantial percentage. I could be wrong, of course.