It's not just about cost. AIUI, from browsing /r/spacex, it's about feasibility. Less demanding payloads will have enough fuel to return to launch site, some wi

It's not just about cost. AIUI, from browsing /r/spacex, it's about feasibility. Less demanding payloads will have enough fuel to return to launch site, some will have enough to land at sea and some payloads will require the use of an 'expendable' configuration where too much fuel will be used to recover the rocket. Expendable launches are more expensive.