The worst case now for Boeing is a series of disasters that leaves the public unwilling to fund anymore space thus killing not only SpaceX, but also Boeing. If Boeing sabotages SpaceX not only do they risk that they also risk getting caught by the investigation which would be bad for Boeing. Note that unsuccessful sabotage meaning you are caught is a real risk as well.
NASA can not count on the SLS to do the job, if only because it costs do much to launch the SLS that NASA can not afford many missions with it.
that's been the case for almost a decade now. just replace spacex with the soyuz rocket.
Instead NASA would launch an intensive investigation, discover Boeing was behind it, and pass the data on to the Department of Justice which would indict the people responsible for murder, and that would be the the end of Boeing's space division.
In the case of the second Boeing 737MAX8 crash that murdered more than two passengers for which the finger of blame points towards MCAS the blackbox audio recording will never be heard in evidence although it sits somewhere possibly in a Government's office.
Yeah, Boeing is going to sabotage this launch, just like Big Oil, Big Auto, Big Media and Big ShortSeller sabotage Tesla.
These companies have a delusional fanbase.