the point people are making is that if you're bowling well and knocking the opposition over you'll put pressure on their bowlers and make it easier for you to post good scores even if your batting lineup isn't particularly good.
I've always wondered about this. If your bowlers go out on the morning of the first test and hoop the ball round in circles, beating the bat two or three times an over, and skittle the other side for 200... I dunno, I'm a lot more concerned coming out to bat immediately afterwards than if the other side have racked up 500. I remember Sri Lanka racking up a HUGE total against Pakistan in the opening match of their doomed tour there last year. Younis Khan came out at the end of day two and ranted about the PCB being dicks for making such a flat pitch. Then promptly scored just under 300. The weight of all those runs sure as hell didn't bother him.
Of course, runs are subsequently valued less. A 300 chasing 500 is considered hopelessly inadequate, but when facing 200 it's considered a good effort in what are then concluded to be difficult batting conditions. Is it really easier to
reach 300 facing a big total than it is facing a small one? Does quality bowling give batsmen a mental edge, or does it merely make their totals seem better because they're
enough in one case but not in the other? Corrin referenced the English batting lineup regularly making 400 in 2005- fair enough, it was
enough, given their bowling attack- but I remember their 2009 counterparts being slaughtered for only making 400 in the first innings at Cardiff.
And on top of that, there are certain opponents for which the complete opposite of what you say is undoubtedly true. If you bowled out Steve Waugh's Australia for 200 on the opening morning they'd come back at you twice as hard. Your chances of making 350 are inversely proportional to how low a total you had the cheek to bowl them out for.
So much of cricket is played in the mind, but the mental effects of certain activities are so difficult to quantify I often find myself concluding that it's not even worth bothering.