We own them legally speaking yes but excluding pogba and Vidal (since its unlikely that both will be here in 2 years), all the attacking players havent scored a handful of goals combined wearing our jersey. What you posted IS a new starting 11. Bonnuci and Marchisio are the only starters from the current starting 11 and neither is a key player in the sense tevez and pogba are now or vidal and barzagli were.
Cacares and Ogbonna are bench players and the same goes for Pereyra, Morata and Coman. Also all of them except maybe Cacares are question marks.
Still my point is that even if all our current bench players perfectly replace our starters and if our youths that ply their trade on loan turn out to be great and if Asamoah becomes a good lb, thats still pretty much a new team that will take time to fire on all cylinders. Roma's team on the other hand will be a more gelled version of what they already have + - minor changes.
You are really undermining the scale of change that we are about to go through. We are losing our goal keeper and captain in buffon, our main creative player in pirlo, our best defender in barzagli and our best young player in pogba. Losing these four players alone is massive change in our game plan, on who is scoring the goals, who marshals the defence, who is our main playmaker, ... everything changes and that is ignoring Licht and the other older players who are less central in how we do things on the pitch.
Again I am not saying that we wont find replacements, we might actually build a better squad with our increased financial strength and our improved brand name and the Pogba money. All I am saying is that our cycle is ending while theirs began last year. They will peak while we rebuild and they have an advantage until our new cycle is in place. If they dont beat us to the title atleast once then they really suck.
If you want to feel the scale of change, imagine Madrid without Ronaldo, Benzema, Modric, Marcelo, Ramos and Casillas. Even with their insane bench and with their huge resources thats a giant change that would give Barca an advantage