I think the reason everyone was so angry about the Xabi/Poulsen situation, was that Cobolli had claimed that we would be buying a similar caliber player to Amauri for the midfield position. I remember this specifically, but I can't hunt down a quote at the moment.
So we spent 22.5M euros on Amauri, which made everyone feel like we were going to be able to afford the 16-18M+ (approx) for Xabi. Then we totally lowballed Liverpool (with a pathetic offer of like 13M or something, I do believe), which made us look a bit ridiculous. Everyone with half a brain knew that Xabi had been injured, and would return to form with continuity. An offer in that range was silly... and it was a little embarrassing to see the ineptitude of our board so blatantly on display.
At least this was my interpretation of the situation. Because we only spent 9.5M on Poulsen, it's clear we just didn't have the available funds to be in those long protracted negotiations in the first place.
I still think that we should have tried to find the money somewhere to make that transfer happen (I'm sure we tried to move people, but maybe a loan?). Paying a reasonable price for quality often saves money in the long run, and if Sissoko was worth 13M, our board should have recognized the type of offer it would have taken to make that Xabi deal happen.
This is just my opinion based on uncertain variables, and I could be wrong. I do really admire Alonso though, and he would have been a fantastic asset for this club going forward.
Edit: Here's an incredibly oversimplified and general example (which I heard for the first time a few days ago, and was repeated today): The difference between 2 and 3 place is worth 5M Euros in prize money. For some reason, I feel that had Xabi been a part of this team (and barring any unfortunate injuries), we would probably have 2nd place on lock down by now.