Why is all gear drops/gambles in the first 3 acts so unbelievably bad?

I gambled 30 body armors level 34, the best one was 40 life and 9% resist. Every piece of gear is trash, complete and utter garbage. Ok, I get it, the goal is to reach Act 4 and buy stuff from the market, been there, done that, but this complete and utter lack of useable gear just makes slogging through the first 3 acts a pain. I get why trading is locked behind that, I don't get why drops have always been so unbelievably bad at the start.