Both Workflowy and Dynalist were treated as finished software for years. Workflowy did pick up again when it started losing customers.

Subscriptions do motivate ongoing development, but only if there's a threat to stop going or start incurring subscriber losses. Product software categories have different ratios of customers who buy subscriptions for the current utility vs the investment into future utility.

Long-term heavy Workflowy and later Dynalist user here. I am not upset that the developers started working on Obsidian instead, since I see Obsidian as the superior product, which has replaced both Workflowy and Dynalist for me.