Why can't you fully unlock stuff through single-player?

[Axe99]

G'day guys,

While I'm an online gamer, and have already played some games online and plan to play plenty more, it's disappointing to see that to unlock a lot of the stuff and better planes you _have_ to play online. Given half of the XBox crowd hasn't paid up for online play, and around a third of the PS3 crowd aren't online, it's a decision that could leave a bad taste in their mouth.