Green Armadillo has pointed out the strangeness of dual spec being so expensive, and fairly late in the leveling game. 1000g is a lot for a new player, so they're not likely to get it right away. Keep in mind this is new new players. I'm talking about the troll shaman who put his first points into improved healing wave, thought respec would make him lose all his abilities, and who never casted spells despite being elemental because he always ran out of mana. This isn't about alts, or even new server rerolls.
For those players, gold isn't even the real issue. The true problem is learning. Playing as the wrong spec for a role causes problems. Experienced players can tank as ret and heal as shadow (I have) or whatever other wrong combination you can imagine. We have a strong grasp of how healing, tanking, and DPS work and can adapt to a suboptimal spec. New players don't have that experience. They can learn of course; I did. But what are they learning? Playing a role with the wrong spec tends to teach bad habits.
My priest would start throwing mind blasts at low mobs hoping for the killing blow spirit regen and tended to use dispersion as a regen crutch. She had no concept of which healing spells to choose, since none are boosted at all by a shadow spec. Do I use flash heal? Greater heal? Maybe I use renew and player of healing? Talents act as guides: disc talents encourage the use of PW:S while holy talents encourage renew and flash heal. This won't guarantee perfect play, but it will give some concept of what is for what.
Until I went prot at 50, my warrior would tank instances in berserker stance throwing whirlwinds for aggro. Defensive stance and a shield? Not gonna work. Well maybe now; this was a few years ago after all. I was hell for my healers. But at least I topped the meters. That's what matters, right? It took a while to learn what to do in defensive stance, since I barely ever used it.
Dual specs might also help to teach the difference between solo and group play. The act of zoning in and switching specs reinforces that you're in a different role and environment. It's like changing clothes. It changes how people act. This probably won't help much with DPS, but for tanks and healers, while leveling it could help to teach them that they are part of a group. Or maybe it would help DPS. They'd run off and pull while healers are still drinking and don't yet have the regen to bail them out of their stupid. Dead DPS learn faster than bubbled DPS. But getting back to tanks; how often do you see tanks, or DPS, or healers, who seem to play as if they are still soloing, but their health sometimes goes back up? Switching specs would be a message: "You are not soloing anymore. Act different."
Blizzard has tried to make leveling easier with cheaper mounts at lower levels. But how much do mounts really change the game? If it's a short distance, not much difference. If it's a long difference, that's when you pull out a book to read along the way. They affect us while soloing. Dual spec, that affects us in groups. It might just be my bias, but isn't group play really the more important aspect of the game? That is where we affect others, for better and for worse; where we create a community (or not thanks to cross-server); where we learn our roles beyond "read quest helper, kill, repeat."
Before 30 the specs aren't significantly different; but after 30 they diverge much more, gaining their unique flavors and styles of play. By 40 they are clearly different. But what new player has 1000g at 30 or 40? I certainly didn't. While I am well aware that low level players can make tons of gold from gathering low level mats, that's not always apparent. I'd even argue that it's something they shouldn't know. Let them level their crappy crafting profession that they think goes with their otherwise profitable gathering profession. It helps the immersion. It gets them into the game. Don't tear them away from their ignorant bliss too soon. Leave the gold sinks to the 80s who should have by then learned the cold reality of the game.
Wouldn't it make more sense for the luxury of mounts to have a luxury cost, and give the necessity of dual-specs a cost in line with any other necessary training?