In cases like above A pillar blocks the view. If one looks closely you can see car did react and apply brakes but there wasn't enough space for the car to slow down and stop. Cars have minimum stopping distance depending on the weight and speed of the car.
In this case the car hits the bike and drags it down the road for few meters. That's inertia for you. It didn't hit a 2 ft thick concrete wall that it would freeze right there.
In countries where people have even a little bit of road sense don't expect some one to come on the road in front of them like this. Biker was supposed to slow down and give way. Car had the right of way.
People on bikes don't know there are many blind spots in the car. Car drivers can't see in all directions all the time. Mundy phirky ki tera nahy ghumty un ki, or na hy koi super power hoty hai un k pass ik dam gary ruk jai, reaction time bhy koi cheeze hai.
In countries like Pakistan most car wale khud ahteteyat karte hain k pata nahy kahan se koi pagal moon utha k agey a jai. Main normal driving keron jaise main overseas kerta tha, main beghair koi rule tore 40-50 motor cycle wale neeche de doon her roz.
Motor cycle wale and a lot of times cars wale left/right se cut mar k aisa fakher mahsoos karte hain jaise bara paul walker wala scene kiya hai. Un ko nahy pata hota k gary wale ne agr brake na lagai hoty to us ne wooooooooo ja k parey hona tha.