The recumbent bicycle segment
The recumbent bicycle segment is a very small part of bicycle production and a MBB design, in this case Cruzbike, represents an even smaller market share. I wouldn't say that Cruzbike is in a unique position of creating new versions and models; the changes we are seeing on the Silvio and the Vendetta represent long-term R&D, much of which is based in real-world application. The amount of time and resources in making even a slight change in the design is the result of much time, labour and monetary expense.
If you think of it in mainstream terms, look to the manufacturers of typical racing bikes. These are companies that are able to throw large amounts of money toward team sponsorship (exposure and real-world R&D) and internal R&D (finite element analysis, wind tunnel, simulations) because they offer a broad product line which brings in revenue from which they can allocate their expenses on the best methods by which they can produce the highest-perfomance bicycle possible. And for this, the consumer is willing to pay a higher cost, which may or may not be proportional to the advancements made.
With that in mind, many enthusiast cyclists will buy the "latest and greatest" and will happily sell and take a financial loss simply to have the newest technology. If the company producing said bicycle would offer a trade-in promotion to these riders, they might get some interest, but in the end the company would, through their supply chain, have dealers handle a trade-in program to handle the inventory from bikes that were traded in. I think it is common that a better return comes from the resale direct from consumer to consumer rather than seeking a trade-in allowance.
In the end, a manufacturer's best interest is to supply and move new inventory and there is basically no incentive in this industry to become a retailer of pre-owned equipment. Your Silvio is a fine machine by any standards, and you are fully aware of that. The releaase of a newer model should not diminish your enjoyment of your bike. The good thing is, there is a strong second-hand consumer-to-consumer demand for your bike, or if you choose, just the frame and accessories as supplied by Cruzbike. Your Silvio will still command a strong resale value when the time comes to sell. So rather than be concerned about a trade-in program, plan for the day when you are ready to upgrade knowing that someone will willingly pay a fair price for yours.
Finally, never think of the financial loss when selling a bicycle; rather think of how little you paid per mile for enjoyment, health and overall well being.
Thanks for reading.