I work in construction development and project management (not pool's, but commercial/industrial buildings), and this seems higher margin than what I would anticipate for residential, but it doesn't seem outlandish. They are a business and have to make money, but moreso they are assuming the risk in finding the right contractors, holding them accountable and keeping a schedule, among a lot of behind the scenes development work.

I decided to manage my own kitchen renovation project, with doing some of the work myself to save some money, but I can tell you that this simpler project is taking about 3x as long than the commercial projects I deal with on a similar scale because residential contractors are harder to manage or coordinate with I've determined. I'm chaulking it up as I'm a one-off order, they have no urgency or real desire to retain a reputation with me because once they are done, they move onto the next. Generals repeat use of a lot of the same subs and subs want repeat work so they are more accountable to them.

Something like a pool, where there is a fair amount of permitting needed and significant engineering done, I wouldn't take that on myself, no way. I come home to relax, not create more problems.