>> - Halo was announced in 1999, originally planned as an RTS for Windows + Mac, not for the launch of Mac gaming (not Mac only, although prior titles were focused on Mac only)
> How I read the OP (at least for this bullet) is in line with what I remember at the time: Halo was originally a Mac exclusive, and us Mac gamers (there were dozens of us, dozens!) generally perceived it as being the beginning of a golden era, where Mac would be taken as seriously as PC for games.
That's how I remember perceiving it: finally a Mac game that the PC gaming kids would be jealous of. Also, I think it had already evolved into a FPS before MS bought it (I remember thinking the vehicles would be really novel and compelling feature compared to PC FPSes).
Gaming with a Mac was a backwater in the 90s. All the popular games would get a belated Mac port, if that (e.g. by the time PC gamers moved on to Command and Conquer: Red Alert, I just was able to play the original Command and Conquer, and Red Alert was never ported at all). Bungie's games were Mac-only and good, but (for instance) by the time I played the Marathon series, the tech was dated.
Edit: corrected mistake, I was thinking about Command and Conquer/Red Alert, not Starcraft/Brood war.