To be fair, while Apple has used previous WWDCs to announce new hardware, it's not the "right" place to do so.
It's a good platform given how the whole world is watching, but it does rob the developers of their recognition, and I think that putting the sole emphasis on them this time around is really saying a lot.
Without the app ecosystem, the platform would not be quite as comprehensive or worth the investment. This time, I believe treating the developers with respect and not stealing their limelight was a good move on Apple's part. No other platform treats their worldwide developers with as much respect.
/Dan