Lifetime license fees are not a sustainable business model over the long run. We have seen that with apps or other software. Everything is moving to a subscription model, both because the economics work better for valuing the company, and it makes for a more sustainable business. Especially if growth levels out and the company isn't acquiring a lot of new customers, but still has a large installed user base.
One would hope that with an annual license fee that C4 would be less incentivized to EOL their hardware. In the past how would they make revenue from existing customers? To do that they had to sell more hardware and one way was to make them drop $10k on new controllers every 5-10 years - not that I am saying that they did this on purpose.
Even think of Apple today, they are trying to purchase their service revenue because the market for phones isn't really growing, new phones are generally replacing existing phones. So they are trying to grow services like music, video streaming, news, games, fitness, etc.