According to the pictures you have a 4 piece set that had to
be connected with the sink in place.

No, it's one piece. Yes, you have to put the knobs on and the spout and
spray attachment but the basic unit is one piece like most. It's not
individual valves with connecting lines.

Also according to your pictures all the drain lines are
directly in the way so this guy had
to weave in and out of this mess.

Wow you got me there. The drain lines are in the way? Aren't they in the
way of each and every single sink and many/most double sinks?

and in the tight cabinet, upside down with minimal lighting, on
your back with water dripping on your
face. You try it.

What you are describing sounds like ordinary kitchen faucet replacement.
Which others have said goes for maybe 150-250. You're grasping at excuses
for pure and simple price gouging.

No one here knows where this is, a small town in ohio or
the middle of NY city.

Actually, everyone else besides you knows. Had you read my posting I
indicated it was suburban Chicago.