Yes but a reusable rocket will always be cheaper than a one-off rocket. They could charge twice as normal and still be overall cheaper.
evidently spacex's previous proposal had either a technical compromise they weren't willing to take, or it was more expensive than roscosmos.
now oneweb basically has been forced to make a deal with spacex and they don't run a charity, specially now that one of their main competitors is off the market.
I don't know how you go from there to say that oneweb will save money. spacex will make a ton of money, that I don't doubt.