There's a pretty stark difference. The PhD would retain their credibility if someone explained the difference between the short answer and the complete answer.

But that weather dude will lose his credibility, because his audience will feel deceived, not educated.

I have gotten the short answer and a significantly longer answer from a climatologist. The short answer while wrong still seemed like a reasonable summery and quite understated. I can’t say if the full answer would change my opinion, but it seems unlikely.

This exactly. After a year of high school physics and a year of mechanics and electrodynamics, they finally get around to telling you: that was kind of all lies, here’s relativity. And then a month later they do it again for quantum, and finally admit they don’t know what is really going on. But Newtonian mechanics is useful!

Simplified models are not lies, they are true within a defined domain of discourse. That's not what you were describing.

They should state the truth in first year: We have absolutely no final answers for you, and these years will soon be forgotten. You'll earn more earlier taking any job now. Education is overrated in business anyway.

I think we can reasonably treat collage students as adults capable of making informed decisions. Most people failing to finish the physics PHD end up in reasonable places, it’s hardly the trap most people getting a 200,000+$ history degree would be in.

An omission really only becomes a lie of omission if somebody would feel deceived upon learning of the omission. Nobody would reasonably feel deceived by your omission of the 0.000000001% cosmic ray hypothesis.