Thats because BMW's are generally made with much higher quality parts and are engineered to be more comfortable to drive and more responsive on the road. Macs are made with he same parts as other computers, only they have been blessed by steve jobs so people think they are something spectacular.
A bit polemical, maybe.
I love how Mac users continue to be painted as nigh irrational. Unlike the auto-industry the computer industry has only a limited number of suppliers. Apple can't and shouldn't make their own hard-drives and chips, nor their own LCD panels.
And even premium, in-house designed BMW has defects and problems.