Yes and no. As an early miner on ec2 I certainly made good money. At one point one of the miners had over half the hashrate and a quarter of a mil ec2 bill. The same miner also sold me 30k+ coins at 0.0008 when cryptonote exchange dipped that low. Playing the several swings from 0.001-0.002 that we had plus offloading a nice amount during the mintpal pump has certainly made it a profitable coin to say the least. Big money as in millions ? Probably not. Big money as in 10's or 100's of thousands. Sure. Also depends on if you held btc or cashed out to fiat. 30k coins at 0.0008 to 0.008-0.01 was approx 24btc - 200+btc. Selling that profit at $500 per btc = $100,000.
Well work it out. If someone had a quarter of a mil ec2 bill then to make even 10x much less 100x the cash out would have had to have been $2.5 mil. That's selling 500k coins right at the top (0.01 XMR and $500 BTC = $5 XMR). That's theoretically possible I suppose but it would have had to have been some incredible (and improbable) timing.
Now all things are possible in trading. The price went from <0.001 to 0.01 so I'm sure someone made >10x. Same with mining. But it just wouldn't have been large quantities. In the first two weeks before the price reached 0.0017 only a
total of 350k coins were mined, divided up among a significant number of miners. Some of those were using ec2 as you say, so a significant chunk of it went to Amazon, limiting potential profits (you've identified $250k, and I'm sure there was more than just that one person doing it).
Anyway, I guess it depends what you consider big money (whether in USD, BTC, or % terms), so that's pretty subjective.
I'm more arguing the point that one of the posters made saying nobody has made any real money out of XMR yet, that's simply not true. Could someone with a quarter mil amazon bill over the course of several months made 100-200k, easily.