I don't really understand your post, taken as a whole.
You start out by saying that if we "keep losing your best players it will pull you [us] back, inevitably". And then you end by saying about Bale "He's good but 2-3 very good player you could buy for that amount will take you further" .... which seems to be the opposite of what you said at the start.
Anyhow, as it happens I think we're in a win-win situation with Bale. If he stays another year, then fantastic, we'll have a front three of Bale, Soldado and Player X (possibly Chadli, maybe Lennon, maybe a new signing). Or if he's sold we'll have a bucket load of cash to hopefully sign, as you say "2-3 very good player" .... to "take you [us] further."