I think this is mostly correct. Not only are lawyers who aren't trying to "win" not good lawyers, they are possibly breaching their oath. The lawyer has an obligation to try and win, but only after they have done a preliminary investigation before filing the case. There are also some guardrails; your lawyer can't lie about facts they've found out during that investigation, for example. If they do, they can be sanctioned for it. So they can't just try and win at all costs.

With all that said, I think the original point still stands: in most people's minds, an 'ideal' system is one where all the lawyers are trying to seek justice. We just create a less-than-ideal adversarial system as a weak proxy for that given that human nature tends to make the ideal an unreliable expectation. I don't think that's fundamentally different from the PD transparency issue.