Final answer:
It's generally false that Azure service costs decrease when moving from private preview to general availability, as pricing relies on various factors and is not solely determined by the service's availability stage.
Step-by-step explanation:
The statement that the cost of an Azure service in private preview decreases when the service becomes generally available is generally false. Pricing for cloud services, including those offered by Microsoft Azure, can change based on a variety of factors, such as the cost of resources, competition, and market strategy. Private preview of an Azure service typically means that it's being tested and not all features may be available; the pricing at this stage is not indicative of final pricing. When a service transitions to generally available (GA), the pricing is generally formalized, but it doesn't necessarily mean it will be lower than during the private preview. Microsoft may offer introductory prices or promotions at GA, but this is not a guaranteed outcome.