A trade has nothing to do with the extension. Teams do not operate like that. Tarik Skubal is hitting FA still. His agent is Scott Boras. Remember when the Dodgers traded for Trea Turner and then didn't resign him?
Everyone wants to make everything the Dodgers do to be some indictnent of baseball, but that's unfair. Today the Dodgers traded prospects for 2 months of a good baseball player. Why? They develop well. They identify talent well. In fact, the Brewers get a competitive advantage in prospects because they get more picks; they develop well too. They could have beat this (Quero or Lara, for example are premium positions) and still had tons of prospects. They probably should have if we are being honest.
This is not going to change the next CBA, however. This isn't the first time a very good team traded prospects at the deadline to get the best available player. I get that people are tired of the Dodgers doing things and would like another team to sign Skubal but the Dodgers ability to sign him hasn't changed today. I get that people are tired of the Dodgers winnings things too. I don't really find this a uniquely "Dodgers only" way of doing baseball, however. They may have the financial ability to out kick their coverage of prospects down the road, but this is more about their ability to be a good baseball organization than anything. The Brewers have the ability to out kick their coverage in prospect acquisition getting comp picks. They probably should have leveraged that here themselves.
EDIT: Ken Rosenthal wrote an article about it today that is quite measured. And I think it explains this in a way I can't. Basically, the Dodgers are good at this. At all of this. Yes they have revenue sharing issues and yes, they have a benefit in finances that others don't. But this trade isn't really about that, either. Source.