Is that it? Landing boosters is not saving money as of now. Because a rocket engine is not a rental bike.

Hmmm I wonder if there was a tech that recovered a spacecraft and tried to reuse it to cut costs... hmmm... no, nothing comes to mind

Also SpaceX is charging Nasa more than russians did when they had monopoly over space flights.

Landing boosters saves money and helps with cadence.

SpaceX is charging NASA less. Even Boeing is charging NASA less than Russia.