I haven't done a statistical analysis, but just watching decades of football, it seems that the veteran NFL QB's have much better preseason stats than they do regular season stats.

Typically they start the 1st Q of a preseason game, go 7 or 8 out 10, and get a TD, and they're done for the day. I'm talking about established starters.

The defense hasn't game-planned for them, they are sometimes throwing against backups on defense. Or the DC has specific formations he wants to try that have nothing to do with that QB's strengths or weaknesses, etc. It's vanilla. It's easy mode.

So if a QB struggles against that, it isn't a good sign. And if he looks good, it doesn't prove too much because he isn't being challenged yet.

So I agree with your stance. If Goff does well in preseason, it's better than sucking. But it's not the real test.