Buying someone might not be but who we buy could very much be linked.
For instance, say we have £15m to buy a striker. There is a limited number of options for that money and using it to bring Adebayor in might be the best bet. Now assume we sell Modric for £40m and buy say Moutinho for £30m. It would then be possible to use the extra to supplement the striker budget and look for a £25m striker.
I'm not saying we have defined budgets for striker or any other position. The key point is that deals may have affects on each other. We will be looking a several strikers and several midfielders, plus a few other positions as well. For each position there will be a range of prices and targets will have different availability. Who we get for one position will affect the possibilities elsewhere as we can't buy the most expensive option in each position. If a player we like becomes available it will have knock-on affects. The calculations will be further complicated by payment terms and cash flow.
So we might be confident we can sign Adebayor at any time by making a concession, but still holding out for an alternative, one that needs extra revenues from sales, or a player who is interested but still hoping one of the bigger clubs are interested. The apparent inaction doesn't mean we are doing nothing. It could be a sign that we are trying to get better players and a sign of ambition.
