In my opinion Marotta won't put mega offer for players over 30. During his Juventus career he was really careful while buying new players and most of the old players he bought was free transfers or real bargains like Barzagli. As far as I know Marotta was against Ronaldo transfer due to his age. I think the only exception was Higuain, he was 28.5 when Juventus bought him and it wasn't best deal, he scored many important goals, but he didn't help Juventus to reach another level (Champions League) and he had to make space for Ronaldo just 2 years after his arrival.
So I think Vidal, Matić or Rakitić can arrive to Milan only on loan.
Another example is Dzeko, which is 33, and Marotta didn't want to put just few millions more on the table, because he knew that it's too much and it could block future transactions.
The other aspect is Inter's first squad age. Most of the core players are young (Lautaro, Sensi, Barella, Skriniar) or at their peek (Brozo, De Vrij, Lukaku). The only core player which is over 30 is Handanović. When it comes for Juventus it is difficult to find core player before 30 (Bonucci, Chiellini, Ronaldo, Higuain, Matuidi, Khedira, Cuadrado and Costa, Pjanić, Sandro, Szczęsny are almost 30). It looks better in Napoli, because they have young Ruiz or Zieliński, but their best players from previous seasons were Mertens, Callejon or Insigne and it is likely that Mertens and Callejon won't extend their contracts while Insigne is worse player than in Sarri era.
So I think it is crucial for our management to think about long term solutions, not temporary ones, because it seems that the gap between Juventus, Napoli and Inter will be even smaller in coming years and our money should be spent for players younger than 26 like in the summer mercato. Yep, we could run the risk and buy Dzeko, Vidal and Rakitić in the summer, we could win the Scudetto maybe, but what's next? In the next year we would be out of the money and we wouldn't be competitive for Juventus anymore. Juventus have more money, so our management has to have a strategy to win with them.