Ok...but he has the budgets and $ to hire players, midi wranglers, orchestrators and copyists just for a demo. The users polishing samples for weeks are probably using them as the end product.
Well, currently I work as a MIDI wrangler. Also known as Synthestrator. So I can tell you that synthestrators aren't spending weeks on demos either. The time scales just don't exist. I am looking for libraries that sound 90% great fast and, even more importantly, for the 10% lack of realism that remains, I know what controls to change to predictably make a desired change in the sound. Inconsistently programmed libraries are a huge unaffordable time sink because they force a synthestrator to sit there and experiment with all the control options trying to get to a goal sound.
to be fair, I'm pretty sure CSB and WA have probably the most ridiculous top dynamic of any horn library I've heard ever. You'll never get players to put out that much air in real life anyways - so it's not a tremendous loss. CSB is blistering, and if WA had 4 players with the same lungs on them I think I'd be pressing charges.
Outside of those 2 libraries - getting a LEGATO patch with that amount of cuivre is pretty wild. I'm not sure what music you listen to that features that dynamic held for any reasonable length of time. Maybe you're confusing real life with a whole generation of sample music?
The top dynamic level of CSB isn't meant for sustained playing. It's not realistic to do so and indeed, the sample are only a few seconds long so you can hear quite audible looping on some notes (mostly horns).
So why even record that level of dynamics? I think Andrew W put it very well in one of his videos. You're not going to use fff often but when you need it, it has to be available. I use it on things like the final push of a crescendo. Or when you're playing a staccato ostinato that's been moving from f to ff and the last note has to really BLAST, then you can use fff. For the most part, keeping the modwheel at 100 for CSB legatos (70 for marcato legato) is as loud as you'll ever want orchestral brass to get. Until you need fff for those special moments.
You don't notice a ceiling - until you bump your head on it! Then it's frustrating.