The GLF saw steel production alone go from 1.3 to 23 million tons and electricity improve from 7 million to 133 billion kilowatts-hour. Heavy industry output increased by 230%, total food production rose by nearly 170%, industry in Chinese gross national development rose from 36% to 72%, divorce was legalized and women's rights in China moved forward by decades, average income for workers rose by over 30%, capital investment doubled, life expectancy raised by ~22 years (from 1960 to 1976 as a whole, mind you:
World Bank), the cycle of famine came to a total halt (China went from having two famines roughly every decade to not having a famine in over 70 years after the GLF), and tractor and fertilizer production exploded.
There are obvious things to criticize about the Great Leap Forward (such as the relocation of farmers to urban industries leaving grain to rot, the Four Pests Campaign, local officials inflating agricultural numbers, and many other mistakes too numerous to list, many of which directly influenced the Great Chinese Famine) and things outside of government control that would've led to food insecurity anyway (unusual weather patterns during the late 50's and early 60's were very impactful combined with China being a famine-prone country at the time already), but to say it was a "total failure", didn't help China at all, or that China "didn't industrialize until Deng" (China's industrialization
is what made Deng's 'reforms'
so successful!) is backwards. The Great Leap Forward was a massive industrial leap that directly led to China's position as a world economical leader now, for better or worse. Its successes led to a massive increase in industrial output, the breaking of the brutal cycle of famine that had been a part of Chinese life for nearly a century, and increased global relevance. Its failures (and debatably parts of its success as well) led to the rise of the offshore nearly slave-based economy we see in China now (Thanks, Deng!) and, in part, the Great Chinese Famine. Not to mention that the US pressured other western countries to stop grain shipments to China during the famine!
Edit: Also, "45 million people". Dikotter and his consequences have been a disaster for the human race. I'd recommend taking a look at
this article by Monthly Review for a decent series of criticisms around inflated death tolls due to the Great Chinese Famine.