Most would possibly agree that the quality and longevity of FSX is, in large measure, due to the array of addons (free and pay) that have emerged over the years. It took Microsoft management awhile to allow an SDK. They seemed focused on the success of the closed Apple model. Once the SDKs appeared wonderful addons showed up and it was like getting a new product.Now we are faced with an allegedly closed product as a follow-on to FSX. This presents some problems for those loyal addon producers. If a sizable number of FSX users move to Flight the customer base remaining for FSX will shrink. The authors will see no opportunity to move their wares to the closed Flight and may shutter their virtual shops. This will dry-up the addon products and FSX will simply die on the vine as the remaining base seeks a richer flight simulator environment. In-other-words Flight may become responsible for ruining FSX.