Most modern games offer all content but the latest big expansion for free or at least as part of a reasonably priced package, not nickle'n'dime players charging 100s of USD for 10+ year old content. Nobody is gonna stick around once they find out that 95% of the game is behind and paywall, that is if they even decide to stick around because the low-level free quests are some of the oldest and least enticing in the game.
In the past, this is where the VIP sub would come in, offering essentially "trial" access to all content for a reasonable fee. But for years now, VIP can no longer fill that role because it doesn't give access to some of the most relevant content that most current players have gotten years ago, for free or at a heavy discount.