I've worked on big and small. Even for the 'big ones' the (there were network management apps) - the 'business logic' (networking logic in this case) - was not

I've worked on big and small. Even for the 'big ones' the (there were network management apps) - the 'business logic' (networking logic in this case) - was not rocket science in the end. As you indicated, not only is the 'layering' a pain, but often there's a whole set of technologies and toolchains at each layer! Even just starting with 'identity' for a web app, i.e. Facebook and Twitter integration along with basic credentials - can be a big pain.