1. Isn't this true of anything that requires money to be made?
No.
Quite frequently, marketers keep their attention focused on how to sell a product that is already completed by the experts who are making said product -- they don't tell you what you should make, they focus on selling whatever it is you DO make. Arguably, its when the marketing department gets too involved that the issue of artistic integrity (and, related, authenticity and quality) comes up: when a TV show adds an ancillary "adorable child" character in the 5th season to boost ratings is one example that often goes awry.
Of course, it can also go well, giving the creative minds more fuel for the fire. If we're gonna use the "extra character" analogy, I don't think anyone would argue that, say, South Park has suffered from the introduction of Timmy or Jimmy or Butters.
It's not really a good or bad decision, right out of the gate, but it is a decision that carries certain baggage with it.
2. Is it a matter of "it wasn't sexy enough" or "we want to make it sexier than it was"? There is a very fine difference there, but a difference none the less.
If you have to make it sexier than it was, then it obviously wasn't sexy enough for you.
One case in point (but also IMHO): half-orcs. What does a half-orc do that the 4E orc player race writeup in the MM not do?
For one, it gives you an interesting and conflicted back-story, being halfway into the civilized world and halfway out of it (kind of like the original tiefling flavor did for them). But 4e absolutely posits that sexiness is not in that kind of back story, or, at least, not ENOUGH in it to warrant how sexy the dragonborn are.
Another: sorcerer. The difference between sorcerer and wizard was -- in my experience -- that sorcerer rarely got used by players. If 4E gives it a very distinct feel from the wizard, then I'd say it's worth the wait.
I'm pretty sure that if the WotC folks wanted to make the sorcerer distinct, they could have and would have. They didn't really want to (yet), though. They wanted to give you sexy warlords and warlocks instead. These have the further benefit of being new hotness, breaking with the older edition, and further increasing how D&D can stand out in the fantasy melieu (whereas a "variant wizard" wasn't really one of those ways).
They just don't really care if you can't convert your sorcerer character right away, because the new hotness is more important to the strategy of the brand.