Of course, the negativists are saying "gee, if their sales are locked in for the first five years of production, as their chief sales goon claims, why are they advertising?" I think they realize a number of folks purchased and ultimately held onto positions as investments, figuring they'll sell those positions for a healthy markup
Our flying club has a waiting list now. We are still investing in a little marketing. For the past number of years we've brought an airplane over to the Wings of the North Air Expo across the field. I just authorized the $350 for this year's exhibit. We want to keep our name out there. We won't always have a waiting list. :)
Because if you wait until you have openings to advertise (club or manufacturer), you have to wait for orders (members), and have a time period of open slots.
Also why, when we had our consulting company, I preferred to have a number of smaller customers, rather than one big one. With one big one, you have good income, until you don't have any income, until you can find another big one.
With a lot of smaller ones, you get variable, but steady, income.