I'm pretty sure the Long March rocket first stage attaining orbital insertion was not accidental
The Long March 5B has no second or third stage and the first stage is non-restartable. Therefore it will inevitably end up in orbit with its payload.
The 5B is powered by 10 engines; two YF-77 LH2/LOX on the core plus two YF-100 staged-combustion engines on each of four kerosene/LOX strap-on boosters. The boosters separate 173 seconds after liftoff. The core stage burns all the way to orbit.
(The baseline version carries a restartable hypergolic upper stage, with two YF-75 restartable engines, weighing 12 tons which is omitted on the 5B to maximise the payload which can be carried to LEO. ).