Well how come he hasn't had a serious injury for so long then? It must be because of the changes he belatedly made - it happens. It happened with Djokovic when he made changes and it happened with Messi when he made changes too.
We'd already spent money on forwards in the Summer (£30 million or so), if we were that desperate for another striker there is always another opportunity in January.
And who cares what anybody said on here or in the media? We get things wrong all the time. We aren't privvy to all the information (although I didn't think he would break down, based on the fact it hadn't happen for a long time). Saying you'd expect Diaby to be fit for a whole season is disingenuous because they don't have the same physiology and they haven't had the same injury problems. Diaby can't avoid using long strides putting strain on his hamstrings because that is the player he is, RVP can stay away from making stupid decisions on going in for challenges because he is a striker and at that same time build-up his strength whilst doing that.