Good designers that actually think about their design implementation are rare beasts. Most just draw whatever they like visually like.
Again, stakeholders do not understand how responsive design works. They ask different for different things from desktop and mobile sites.
As a result of things I listed above developers maintain two fairly different frontends.
After a while stakeholders forget we have two versions of the website and plan new features with one (desktop or mobile) version in mind. Some developers just send them back to drawing board, some implement whatever they ask and add even more fragmentation.
Yes, show your developers matter. I didn't realize this until I joined my current workplace. Asking for IDE license? (approx 1/20th of my monthly pay): "We'll look at that". Multiple times. Complaining your machine is crap? (laptop with 4 gigs of ram, maxed out): no reaction at all. Asking HR to purchase bicycle via cycle scheme?: "We'll look at that" (3 months now, not a single step taken). Needless to say I'm looking for a new place.