Steam is the one that forces you to download all patches before playing games. Yes Rockstar is dumb in how they handled this update but Steam is actually "enforcing" it, as it were.
While it does make sense for MP-portion of games to force patches so everybody plays the same-version...
...but, on SP-portions of games - yeah, you kind of do have a point: Steam program itself forces updates on all game.
For SP-only games, it really should be up to the player to decide to take an update or not.
But, really though - Rockstar is selling games on Steam, so they should do things logically to satisfy their customers that are using Steam's delivery system. They know how Steam works - so they should've come up w/ a better solution for this platform than what they come up with. I still think it would've been easier for this kind of update b/c of how Steam works (i.e. forced updates), if Rockstar just added a brand-new San Andreas HD entry for sale on Steam entirely; and stop selling the old San Andreas version until they decide to renew music license or just not sell that version anymore at all. And Rockstar could've gave the new SA HD Edition for FREE to SA old-version owners, just like other games have done on Steam that got questionable re-releases (i.e. Fable: TLC and Fable Anniversary have separate entries on Steam).
I wouldn't also be surprised if Rockstar figured to avoid any lawsuits at any turn, they made this decision w/ this thought in mind: "Well, the MP3 ratio station is still there - modders w/ old-files can unpack the files and convert them to MP3's; or those that have their own MP3's of any tracks removed, they can put just it back into the game in the MP3 station at Documents\GTA San Andreas User Files\User Tracks folder themselves."
