I think some of us have a different definition of what is "pay to win". For instance, I don't consider GTAV:O a P2W model. The reason is due to the fact that players are simply buying in-game currency with real money. ......currency that all other players can still obtain themselves (without paying extra) through activities in the game.
On the other hand, many free to play games are prime examples of a P2W model where players literally can't obtain the same, better weapons, vehicles, etc. that paying customers can.
That's not to say that I don't agree that Shark Card purchasers don't have an advantage over others, but what separates GTAV:O from the P2W model IMO is that the player can still make cash in their game and still buy the same things Shark Card players can.
In a nutshell, if items that provide an advantage in a game are offered exclusively to players willing to pay for them, I would call that a classic "pay to win" scenario. At best, I would consider GTAV:Os model a shortcut. In either case, I don't think RDR2 will be as "bad" as GTAV:O for various reasons.