Insufficient design controls will result in a loss for the company. The loss will occur first off by the product not making it to market and this will result in a trickle down effect. As the time, money, and energy focused into the product will be a waste and the company will most likely have to make cutbacks and perhaps, depending on the scale of failure, scrap the whole project altogether. Design controls are set forth as a methodology that companies must follow in order to ensure that they are compliant with the FDA. If the scale is large enough this can be a large blowback to the company causing stock to fall, for publicly traded companies, and employees to lose their jobs if not followed properly. FDA will send out warning letters as mentioned by woolyn and state specific violations based off 21 CFR and Design control guidelines. Examples of these are linked below.

https://www.accessdata.fda.gov/scripts/warningletters/wlSearchResult.cfm?qryStr=design+control&sortColumn=&Go=Go&webSearch=true

https://www.fda.gov/iceci/enforcementactions/warningletters/2016/ucm515195.htm