Built to last.
We use 3/4-inch Baltic birch where mass-market carts use quarter-inch MDF. Solid hardwood frames, doweled and glued, where the cheap version uses staples. Locking commercial casters rated for real venues, not the plastic 50-pound wheels you see on import listings.
The same standard goes into the $999 DIY kit as into a $5,000 Custom Elite. That is a workshop rule, not a tier feature.