I've worked in this environment and it's always miserable. Developers are constantly frustrated by way too much upstream information and work and PMs feel like

I've worked in this environment and it's always miserable. Developers are constantly frustrated by way too much upstream information and work and PMs feel like they have no ability to do anything. Even if a PM does the right thing by talking to customers and learning about their pain points, the giant bottleneck in dev capacity means that those customer pain points take forever to address, which often leads to more customer frustration than if you had never talked to them in the first place.