Back in stage 2(or 3) when Alberto lost a bunch of time due to a rubbing wheel Schleck was part of the attack that put some time on Alberto. Shouldn't they have held up for a wheel change?
The cobblestone stage was a completely different situation. Firstly, the nature of the terrain and style of racing on that stage means that there is rarely a peloton of contenders to slow down even if they wanted to. It's every man for himself with riders increasingly strung out due to carnage (flats/crashes), and everybody trying to get a holeshot going into each successive section of pave. Complete and utter chaos/carnage, and why the riders don't like it in a stage race like the TdF.
Secondly, the leaders hadn't established themselves yet by that stage. And any yellow jersey wearer at that point in the race is a temporary holder, not a true contender for top spot on the GC podium. (So no waiting for Chavanel, or Armstrong or anyone.)
Thirdly, no one knew about Contador's broken spoke/rubbing wheel until after the race, so how were they to wait for him? And apparently the broken spoke was quite late in the race, as Contador himself chose to ride on rather than getting a wheel change. Contador as well as the rest of the peloton were already behind at the point of the Frank Schleck crash.
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