Hi Byteme,
Most USB hubs aren't designed for a lot of maximum load devices (which block erupters are). If you think about average computer users, they are more likely to have lower load devices plugged in - mice, keyboards, flash drives and so on, which aren't drawing anywhere near the 2.5W limit. So hub manufacturers design for a lot less than 2.5W per port.
Also, in general, yes it's probably fine to supply more power to a hub, and then run more devices from it. That said, with the current bitcoin mining difficulty, a block erruptor is not earning a lot, and you are almost certain to spend more on a power supply than you will ever earn back...
Flasket, thank you very much for your explanation. Just the type of response I was looking for. As I am looking through page after page of hubs I notice most of them never have "enough" power per port. Your answer definitely makes sense, it still seems like these hardware companies that make USB hubs are cutting corners by not giving bigger power supplies.
Anyways, thanks again for taking the time and give your response.
