> Most local hardware stores carry these giant CNC routers, and the technicians there can cut particle board sheets to requirements.
Do you mean local woodshop? CNCs that fit a full sheet-good are very large and expensive and not at your typical hardware store. Especially once they can load and unload, change bits.
Sheet-good sized CNC's are mostly for batch jobs do not really make sense economically for one off designs. You'd be better off with just panel and cabinet saws.
> How cool would it be if they offered a simplified furniture CAD program, where you could choose what material you need how many shelves of what size, etc and it would generate the needed program that would drill the required holes, and would tell you what size of screws and pins and dowels you need to pick up.
This is most modern cabinetry businesses now internally. Some companies have started offering direct to consumer products, but most are still b2b.