In the long-term we might not have to sell all those other guys. We kept the competitiveness of the squad, make the CL next season too. Now we made money to pay some costs, maybe reduce the debts or renegotiate them with more favourable conditions. Interest payments will kill this club. Did you know we paid like as much interest payments per year we paid to have Lukaku on the team (gross salary + annual amortization cost)? It's expensive to had that squad back then because it was financed with debt.
We are not shareholders but we, even as just fans, need to understand financial limitations. That way we understand why management do certain decisions.
We might have to sell a big player next summer too. But it's so far away it's almost like useless to predict, specially as the ownership is in such a weak position that they might sell the club any given day if proper offer arrives. Not saying it's likely or anything like that but it's very uncertain if they gonna remain here for the next summer.