Will these new distribution centers increase revenue growth?
Not directly, but the distribution centers are necessary to support the revenue growth that will happen "naturally" and growth due to new/improved services. Their main function is to reduce fulfillment costs and time.
Currently Amazon's revenue growth rate is slowing. Its operating expenses are growing at a faster rate than its revenues. Check out Item 7 from Amazon's 1/30/2013 10-K filing.
Amazon's growth rate has dipped below 20% in the past before rebounding. And I'm not sure what you're looking at, but I see operating expenses growing at almost the exact same rate as revenues.
Amazon issued over $3 billion of debt in Q4 2012 to finance its capital expenditures.
They did that to buy land and buildings that they previously leased, so it will pay off in the long run. Furthermore, with the majority of that at less than 1.2% interest (and the rest at 2.5%), it sounds like good debt to me.
Amazon does not break even every year; its net income was negative for 2012.
Does it have to be to the dollar for you to consider it "break even"? They were less than one-tenth of 1% away from even in 2012. Hell, I would even call 2011's 1.3% profit breaking even.
As for depreciation, that is a side effect of that fact that companies are allowed to capitalize PPE investments so that they can expense them over time. Otherwise Amazon's PPE expenses in 2012 would have been $3.8 billion as opposed to $2.16 billion.
It's not that they're "allowed to", it's an attempt to align expenditures with the revenues they generate. This works well for mature companies, but there's a lot of lag for high-growth companies like Amazon. That shiny new facility will show the same depreciation in year 1 as year 10, but it might not reach full revenue-generation capacity until year 5. As long as Amazon can afford more facilities, they will continue building them as the payoff will eventually be that much bigger. Remember, not only do these facilities increase capacity, but they also lower fulfillment and shipping costs, and decrease delivery times to better compete for the need-it-now purchases.
If you want to compare ratios between Wal Mart and Amazon, here you go:
Wal Mart's net profit margin was 3.78%, its operating margin was 5.93%, and its return on average assets was 8.96%, vs Amazon's net profit margin of 0.19%, op margin of 1.11%, and return on average assets of 0.4%.
Why aren't you comparing Walmart's 3.9% revenue growth to Amazon's 20-30%? Because Amazon is still in the hyper-growth phase, although they did post a very Walmart-esque profit margin of 3.68% just a few short years ago. Amazon could shut down the capex at any time and settle in to a Walmart style growth rate and profit margin, but why should they? Amazon is in uncharted territory as far as online retailers go, and there is absolutely no reason not to go for the gusto.