The two events are not really comparable as the rugby world cup is a fairly new invention, with only limited appeal with interest split between a handful of nations in the northern and southern hemispheres.
The football world cup on the other hand is a global event with a much longer history and tradition – all that history is based around the tournament being in the summer in the northern hemisphere, much like how the summer Olympics are that time of year regardless of what hemisphere they are being held.
What i don’t get is why they have granted the WC to a nation with an unsuitable climate AND THEN decide that they need to change the timing of it because it is unsuitable. It’s like they only found out about the 40-50′ Summers the other day.
The FIFA technical report before the bidding recognised all this, Qatar was ranked the worst place to host it and the unsuitability of the climate was a big part of that. The technical committee only provides recommendations though it was the member states that voted for it and thats where the bribery comes in.