I follow 3d printing pretty close but can't claim to be an expert. With that said, I truly thought they served different consumer segments with the only overlap being those who bought a Prusa pre-assembled beleving it to be a one stop shop machine. Bambu is a black box from China for an end user with little knowledge or care of maintaining a machine themselves (down to printing replacement parts)
Bambu Labs' quality and feature set is much, much higher and larger than Prusa's, and the price is right. Prusa bet on people wanting to continually fiddle with their 3D printer, but that segment is already niche and likely dying off.