The lack of side mirrors is because of hyper-narrow roads and gateways and terrifying traffic. Last time I was in India our driver kept his side mirrors folded down... and the man was capable of manoeuvring his car with micrometer-level accuracy. I can think of dozens of times I cringed expecting a scrape but of course he knew his car perfectly.

There are many situations where those mirrors would have been lost if they'd been open.

Manoeuvring a larger truck would require amazing driving skills, and the width of that truck would make adding side mirrors pointless - you'd lose them the first day out.