What do you mean by out of business though?
Just a guess here as I don't wish to speak for Bruce, but I think what he is suggesting is that there is more "to being in business" than simply collecting money and providing a product. When one purchases an addon isn't it implied that support comes with it? Certainly the team here at FSDT spend considerable time and resources supporting their products. You'll note, Issac, that Simmarket clearly states support comes from "Support Forum." That is sometimes true and sometimes not. Many request are left unanswered on that forum. None are answered by Vauchez, but rather by forum members. I agree this comes pretty close to being unethical if not already there. A simple statement stating the developer no longer supports the product and displayed prominently on the Simmarket purchase page would be much better.
I agree Vauchez's business practices are dicey at best. But, that being said I still purchased both of KPDX and KPVD after he had departed and I'm glad to have them. Luckily for me, the little bit of support I needed was provided by one of the forum members. Others aren't so fortunate.
When you purchase something, support is never implied. Support is only guaranteed when it specifically says you have the option of support. Of course, if you have a broken product or have troubles using the product, then you should have no problem getting your money back.
In the case of SimMarket, they state that support comes from the developers themselves (email, support forum, etc.). The FlightScenery product pages display that as the FlightScenery 'Support Forum', which is no longer an active link. I'd agree here, that the 'Support Forum' link shouldn't be displayed and that is where Vauchez is wrong. And sure, a nice message on the site/forum/purchase page/etc. would be nice. All I'm trying to say is it isn't required. However, in a case where you cannot get support from the developer, you have every right to go to SimMarket and demand some help or a refund if you are having problems. Due to the fact that you purchased from them and nowhere do they state 'All Sales are Final', you can go to them.
And yes, the FSDT spends a great deal of time providing excellent, top-notch support. That is a sign of a great business that wants to help its customers which in turn is great business for them.