Tire generators are not common in the US but they are in other countries. Peter White says they're better than they used to be. I haven't tried a new one. I have an old one on one of my bikes. It works, but it makes a lot of noise and drag. I also put an under-BB dynamo on my wife's bike. She may never ride it at night, but it's there if she ever needs it. The sidewall type is reliable, however. It needs virtually no maintenance.

I use a hub generator on the bike I ride the most. I can't feel the drag, and the time and expense have paid off in a big way, since I know my headlight will always work, no matter what.

In my view 400 front and 200 rear are far more than most people need. Most people who use bike lights have lights that put out less, and some people don't even use lights at all.