I'm not using CNC; I just agree with the previous poster that there's an opportunity. (I'd note that none of your subsequent post related to the comment you made about CNC?)
For my project, I believe 19mm is plenty for carcasses - just about every mass-produced kitchen uses 18/19mm chipboard frames, and they can last for decades, outside of abnormal abuse. The main reason for using the same size is easy compatibility with standard doors/fronts together with standard fitment hinges/runners, all of which I'll be purchasing. The tops will be either granite or concrete.
I don't disagree with there being an opportunity or using CNC, I only point out that pinning everything to materials suitable to widely available CNC is too limiting.
Like, using plywood for verticals is overkill, they don't experience any bending, while 19+19 is 48 so you might as well use glued wood board for example.
But CNC isn't the silver bullet. What I ended up with is 25mm glued wood for frames, 55mm for tops and 15mm plywood plus veneer for facades.
If you use 19mm for frames, you won't have enough strength for hinges, which would inevitably be abused.
If you use 19mm for tops, they will sag and vibrate. The best top I have is actually 55mm IKEA glued oak.