Alan Wake is made by Remedy (Max Payne is a PC franchise) and was announced as a PC open world game before MS made it Xbox exclusive.
Mortal Kombat is a multiplatform franchise, it was present on PC since MK1.
These examples aren't relevant.
1) If "Max Payne is a PC franchise" is a rebuttal to Alan Wake, then
by your own logic so too is "GTA is a PC franchise" to the idea that RDR probably wouldn't do well on the PC, a notion
you yourself just presented
2) The fact that Alan Wake was announced for the PC doesn't change the fact it ultimately launched exclusively on the X360; ergo, no pre-existing presence
3) Prior to release of Mortal Kombat 9 on the PC, the previous PC releases were the Mortal Kombat Trilogy all the way back in 1996 and a GFWL-riddled port of the Arcade Kollection in 2012, so it is absolutely relevant (not entirely, but largely)
RDR would probably go the LA Noire route on PC which isn't bad but not good enough to warrant a port of a badly documented code.
There is no evidence outside of Redemption's absence that supports the "badly-documented code" rumour, and I don't believe it holds up under scrutiny:
"Not viable" doesn't really mean anything when it lacks qualification. Many seem to flock to the butchered code rumour whenever RDR pops up, but it's always been incredibly dubious in my eyes since RAGE was developed specifically to facilitate "next-gen" PS360/PC development. The notion that R* had to throw the baby out with the bathwater and stitch together some sort of frankenstenien solution for RDR simply doesn't make any sense whatsoever, and even if it were true it doesn't mean a PC port "isn't viable", anyway -- GTA4 PC was, to begin with, little more than a dump of the X360 version, being completely unplayable on anything that less than a tri-core CPU (it's still a prime example of a sloppy PC port, but it's slightly better now than it was).
Naturally this raises the question of "Well then, why isn't the game on PC?", and I threw my 2c into this as well:
I think, due to the rather modest success of the console-exclusive Revolver (920k LTD in the US, but that's across six years), a PC port wasn't planned at all initially and the immense success of the game caught Take-Two off-guard; with Redemption being followed by LA Noire (somewhat), Max Payne 3 and GTAV, there was no room to slot in a PC port amongst the work that the various R* studios were already doing, so it was put on the backburner.
"Useless outside of his car."
