"The ISS is incredibly more expensive, complicated, and accomplishes less science because it's "international.""
Accomplishes less compared to what? Skylab? Mir?
The ISS is designed to host up to 7 crew members. For purposes of comparison, Mir could host 3. What makes you suspect 7 astronauts can do less scientific work than 3?
Skylab was cheap(er) because it was launched in one single stage (IIRC it literally was a Saturn V cargo bay).
The ISS was designed to be built up over several years, over several launches, with each launch costing much less than Skylab but obviously more overall. It was a design decision that favoured amortizing costs for an age that couldn't afford another Skylab.
Accomplishes less compared to what? Skylab? Mir?
The ISS is designed to host up to 7 crew members. For purposes of comparison, Mir could host 3. What makes you suspect 7 astronauts can do less scientific work than 3?