Tell me why. If we manage to acquire Jovetic, Suarez, and Gotze over the coming years, what would stop us from competing?
Chiellini and Barzagli, on form and healthy, are good. Chiellini, of course, can only grow further. Barzagli, at this point in time, is at the height of his powers, I think, with decline imminent (very few players, even defenders, maintain such imperious form on the wrong side of 30). By the time he's 33 we'll be in need of a new starter. Bonucci I won't even bother with. Caceres is a big question mark. De Ceglie has never truly fulfilled his only modest degree of promise. Lichtsteiner offers a reliable guarantee. So, at the back, we
still, in all likelihood, require a top LB. Not to mention a sure-fire young CB. That'll require a lot of cash.
Our starting trio at CM, when the moons align, is rather formidable - for now. Call me a pessimist but I can't see a 35-year-old Pirlo being up to challenging the two supposedly elite teams of football. Even now he's very hot and cold, he's on the frail side, and despite not playing a physically-taxing role, I have reservations he'll be anything more than a bit player by then. Even now, at one game a week, there are concerns over his fatigue. Marchisio, if he ever lives up to the ridiculous hype, on a regular basis, would be a good to very good player. Nothing beyond that. Vidal's great (with the potential to be one of the top CMs in Europe) but needs to work out the kinks in his game. Marrone's another big question mark to me. Padoin is a non-entity. All this is to say we will require substantial investment at CM too.
Jovetic, Suarez, Gotze - all great at what they do, but do we want Matri as our main CF by then? I don't know.
Say we acquire those three players. One each summer over the next three years. That's the bulk of our transfer budget spent each time, right? Assuming each goes for 30+ millions. All on attacking players. We'd be left with scraps to solidify and improve the rest of the team, which despite looking comfortable in a weak Serie A, doesn't actually have quality depth at all, and many starters of which perform too erratically too be counted on in any respectable CL stage. Barring another financial injection, with our debt and incoming FFP in mind, even with two campaigns worth of CL television money and the stadium income pouring in, I can't see us going on the spending sprees necessary to sort out the team in such a short amount of time.
Anyway,
a long story short, it'll take more investment, and at more places throughout the team (starters and legitimate alternatives), than those three you listed.