It might seem like a good idea, but I'm pretty sure MagiStream isn't a big enough company to be able to afford advertising. Putting those Ads on TV and on the sides of web pages? Costs money. So actually, creating advertisements could be a very risky idea. If they don't attract enough new users, that money is gone, and then MagiStream is in even worse trouble.
The big companies can afford to advertise because they're already making tons of money.
They can afford to risk losing some of it if an idea doesn't pay.