I think that the Padres were prepared to give the cubs an exceptional offer for Contreras and Happ - if they did not get Soto. This put the Cubs in a difficult position. If they waited for it to work out, they would get a great return. But if it didn't work out, other teams that would have wanted the two players went ahead and took what was available. And the deals went south.
But it is not as if the Cubs will get nothing in return for Contreras. They will give a QA, and as a result, will get a draft choice after the second round, but even more important, they get the associated slot money that will run close to a million dollars. With careful drafting such as they did this year, they could end up with the number 11 pick and in addition, a couple of Ferris-type overslot signings, which was probably worth more than what they were offered after most teams had filled their rosters.
But I hope they sign him instead. If they can get him for no more than 5 years, I would love it.