From a business perspective, every manufacturer would like to lease their products and avoid the second hand market. This causes bad trade offs with distribution, and so dealers pop up.
However, all is not bad news. ML has great quality speakers and service support. Their speakers last for years and there are thousands out there. Additionally, there is a moderate revenue stream for panels. Quality service also makes a great impression on the customer and builds good will. How many people hit this site? It's a moderate price to pay and is much more effective than advertising. Nothing beats positive w.o.m.
What happens economically is that the price of the new products are raised to compensate for the used market. Both ML and dealers make higher margins on fewer new products that are sold. There is no free lunch. You squeeze a balloon in one place, and it expands in another place. Imagine how much lower prices for cars, textbooks, and speakers would be if everything was leased?
Also, models are released more frequently with just minor improvements that are marketed as the end of be all. Three years later...
Ultimately, why not be where many of the customers are? As the customers experience the great sound and service, and move up the chain, they can buy new. Sounds like a great business move.