What’s more egregious about this to me is that you’re required to maintain the subscription for what amounts to a one time firmware change.

ECU tuning isn’t something that’s going to need constant improvements and updates like your typical software product where companies can somewhat justify continued development costs. The engine and transmission are what they are from the factory and unless VW is going to send you a bigger turbo or other performance part, your tune shouldn’t need to change past the initial improvement from stock.