Thanks for the lore, friend.
I'm actually hesitant to speak for the members I marched with in this way. My motivations were different those two years as what amounts to a double rookie, 03 on flag and 04 or sabre. But I'll try...
I can say that 03 finals was strange. We were rained out of our final rehearsal runthru, for one. The age outs felt robbed and that was a major factor in the final performance despite some hefty magic extended to us by Myron. We weren't sure, even to the last minute, that we would even have a final show. I was just happy to be there, flying by the seat of my pants, having no frame of reference for how things are supposed to be. Same with my rookout seat partner, who was awarded rookie of the year that season.
Too many challenging things happened to the membership btw 03 and 04 that distracted us from the grit you're imagining. Those things may not have affected everyone directly, but the chain reactions are something I still consider often. I think that grit was likely there for the drumline though, but they were tighter than the rest of us: solid, alumni staff; moved-in in Jan; already had a strong 03 season together where they had carried the rest of us like a boss. And not just in score, but literally, the opener wouldn't have been possible if they hadn't been so tight. But they literally always had fire in their eyes... that never changed based on placement or competition. They were our heartbeat in every possible way. You'd have to ask one of them for more clarity on that tho.
You didn't ask, but I'll take it a step further to describe why I think we didn't place higher in 04. I think the staff and alumni were motivated more than membership in the way you were referencing. We, as members, were stoked on the show in 04, for sure, and it was seen universally as not only highly competitive, but a vehicle for a first place finish. No pressure lol just jump from 5th to 1st, amirite? This perspective is what may keep me in hot water with the org and alum but it's what I believe: in that way, the staff pushed us too hard. Particularly in visual and guard. I still think that just a little more rest both years would've been the key to greater competitive success. Instead, they did the opposite and that's why Vanguard had the rep of the hardest corps back then, even giving Cadets a run for their money. That's why there were silly drops on both finals years. That's why there were still drill mistakes from all sections. That's why a rookie horn soloist cracked in 04 finals when he nailed it consistently leading up to that point, poor thing. When mistakes in such amazing shows happen that late in the season, and when everything else is so pristine, it's not on the members, it's on the staff's ability to motivate appropriately. One of the previously mentioned drops from the sabres was actually 2 drops on finals night from our most reliable, consistent spinner. Our elders, alumni, and staff let us down in that way. Contrastingly, I eked out a sloppy finals but didn't drop. There was a lot of that among the weapons because we weren't confident, we were still trying. And we still had to save juice for the 1st noncompetitive TOC after that. It made things weird again.
The difference is that the drumline could get comments from their finals on-field judge describing how art isn't always perfect if it's truly expressive. Their mistakes were forgivable given the artistry they had captured. The rest of us had staff that found our mistakes consistently unforgivable and "motivated" us accordingly. "The Way" with all its many flaws was in full effect back then.
All that said, IIRC, competition was a motivator for staff and alumni. Myron always wanted members to focus on ensuring we were aware that we were trying something new and breathtaking and to keep our focus there... competitive success would fall in place after we got that. It was the higher calling he always pushed. He always iterated that shows took up a fraction of the summer and that the rest of our time together was much more valuable, so many of us took that to heart. That was my motivation more than anything else. I don't think I was alone in that.