The smarter asians are definitely not lazy and the smarter lazy asians probably go tutoring.
Also, most Asians usually put in maximum effort when it comes to academics which will result in higher chances of better marks.
Also, you don't need to be insanely smart and you don't need to study 24/7 to get good results, examination technique is a huge factor.
Plus, we basically hear this or some form of this everyday 'If you don't get an ATAR above (INSERT ATAR), you're gonna be poor and live your life as a garbage man.'
Basically, the pressure is huge! (Not to mention, Asians are always being compared to their siblings, cousins and family friends who get really high ATARS)
Most Asian parents think that if you don't become a doctor, dentist or lawyer, etc. then you're screwed for life.