I don't know what the next month will look like for Cease, but I will definitely listen on him if I were to get an offer with a strong return. The potential of having a guy for 3 postseason runs instead of 2 should make him far more valuable, and in the offseason teams needing pitching will be more likely to just splurge on a free agent like Giolito rather than make a big trade.
Robert is more challenging. He is about to make his first all start team, and he is under control for 4.5 years! A team trading for him right now would be acquiring the guy for up to 5 postseason runs. The value of this player is so high that it's hard to fathom anyone actually putting the price on the table he would require. The Juan Soto trade, for example, was for a guy who would be under Padres control for 1.5 years, only 2 postseason runs, and he returned several top 100 prospects along with guys who were recent dropouts/graduates from the top 100 and a recent draftee.
Robert isn't on Soto's level, but he's cheaper and under control for so ungodly long. Could anyone imagine what "twice Juan Soto's cost to the Padres" would look like on paper? We're talking about what, 4 top 100 prospects and more beyond that?
The cost for Robert is so high based on the years of control that it is difficult to see anyone meeting it. Most teams simply can't. The handful who have that amount of talent probably wouldn't do so.