Which general domain or area are you working in? Is this your first job?
I also have some imposter syndrome about being a "real" dev. I think that's because there's so many ways to go from here. Whereas, for example, if you were a doctor you would basically lock in your area of practice and then put your head down and get it done. For us, you could: build your own product, climb corporate ladder at BigCorp, startup world, freelance, freelance while traveling, consult, be a product manager instead, etc.
The cushy part is tough to give up, but the free hours don't really make up for the existential dilemma that eats at my soul every day... I know right, first world problems.
I've been on some pretty bad teams and management just tells the lead to task them and deal with it. I once was in a meeting with our manager and the whole team minus the sleeper in which he told all of us (the lead and all junior devs) that it is our responsibility to the team to motivate mr. sleepy. Aside from dead weight, he was also rude and not personable. But I would be too if I had to sleep through the day to get a paycheck.
It's not so much imposter syndrome as it is my unwillingless to let go of good money for a sane workplace. I'm fairly confident I could get a job in a reasonable work environment with legit devs, but i would have to cut my salary by 1/3 or 1/4. And getting paid less to do work - even if it makes me happy to feel productive doesn't seem like a wise choice, on paper at least.
I think the problem lies more in that people are set in their ways and don't want to change. I'm not so hellbent on using hip new tools - like git or an issue tracker - but I push really hard to get people to communicate and interact. Unfortunately, everyone has carved out a niche and there's an understanding to stay out of each others' part of the project.
Maintaining outdated, undocumented applications on obsolete and unsupported hardware and software platforms. Everyone here knows how to do a good enough patch job to keep things moving smoothly.
I openly complain a lot about the lack of any dev process - literally people do whatever they want, including copying the entire source tree to make changes - and absence of any tools. The usual response to change is "go for it and show us it will work", but I'm not familiar enough with the software to go off on a rewrite on my own. And honestly if I had that level of skill I'd be a consultant charge 3x what I get paid.
I have sought a different job in the past and ended up here. Part of me feels like I wouldn't cut it at a "real" dev job and I'm not secure enough to risk a cushy job for the adventure. But it does drive me crazy.
p.s. the guy next to me is sleeping in his chair - this is not unusual.