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Wrong. On a mountain stage, you might just about make an argument for lighter wheels if you weren't already at the UCI minimum; in windy conditions, you might want a shallower front for better handling; but in every other case the aero gain (assuming well designed wheels) is massively greater than the tiny loss from having the weight at the rim rather than carrying it as ballast elsewhere on the bike

1. Is there an issue with weight at the rim (rather than as ballast) and climbing? In terms of momentum, i.e. the wheel 'spinning up' slower? Having never ridden very deep rims I don't know what they feel like.

2. Is every bike ridden on the Pro Tour at or very nearly at 6.8kg? I'm sure I've read a few quoted weights (with SRMs, computers etc.) that were 7kg+ in race spec. Especially the larger sizes, I guess.

And if neither of those things matters, why don't riders run deep rims all the time (barring special conditions like the cobbled classics)? I'm interested to know. Is it psychological?