Personally amazon has helped me a lot with shopping, even when I plan to buy any item offline I check price on amazon to make sure I am not paying too much price.
Last week I bought IFB washing maching (
Serena Aqua SXA LDT 7 kgs), I got it for effective price of 21K on amazon. I inquired about same product offline at Reliance Digital, Croma and Bajaj electronics, all of them quoted atleast Rs.26500. I saved around 5K by buying it on amazon and got free home delivery where as offline stores were charging 500 for transportation.
Not sure if amazon got it from IFB for cheaper price or was selling it at loss but I got product at less price. If Reliance Digital/Croma offered me it at same price I would have happily bought it from them. These 2 stores are backed by Reliance and Tata industries so they are no way less compared to amazon, they can also sell at lower price and compete with amazon but they seem to have different strategy, so saying amazon causing loss to local shops/vendors may not be completely true in my understanding.