This is just regular ole pricing.
Cross AZ traffic is exactly the sort of thing companies with budgets need, that small projects don’t.
If we want to call this just regular ole pricing, it's not a leap to call most textbook cases of price discrimination "regular ole pricing" as well. An online game charges more if your IP is from a certain geography? That's not discrimination; we've simply priced the product differently if you live in Silicon Valley; don't buy it it you don't want it.
Price discrimination has a clear definition. It’s not illegal in the US (when consumers are the victims anyway) but it has a clear meaning and you’re blurring the lines for I’m not sure what reason. Your example of a video game doing regional pricing is a perfect example of textbook price discrimination.
Pricing a good or service at a level that inherently excludes those unwilling or unable to pay is: https://en.wikipedia.org/wiki/Excludability
1. a microeconomic pricing strategy
2. where largely similar goods (AWS with or without substantial inter-AZ bandwidth)
3. are sold at different prices (excessive inter-AZ networking fees) to different buyers
4. based on perceived market segments (most customers don't need (or don't know they need till they're locked in) much inter-AZ bandwidth, but larger, richer corporations likely do)
I'm not trying to blur the lines. On top of any juggling of our favorite sources of definitions, that particular pricing strategy has all the qualitative hallmarks of price discrimination. Everyone still buys AWS, most customers are unaffected by the lack of bulk inter-AZ bandwidth, and AWS can successfully charge much more to those who can afford to pay.
That sounds exactly like what is happening here.
Intra-zone and inter-zone network traffic are two very similar services. One is free and one costs 1¢ per GB. And customers who need inter-az traffic are probably in a different market segment. Now, it is more expensive for AWS to build the infrastructure for inter-zone networking, so it isn't exclusively price discrimination, but assuming that getting more money from wealthier clients was a motivation, it seems to match the definition to me.
Re: excludability, yes it is excludable since there is a price, but that doesn't have much to do with how the price is much higher than the cost to AWS for providing the service.
Is AWS price gouging? Absolutely. But that’s not what price discrimination is.