No one's suggesting such.
We have plenty of disputed behavior and harms that are within the purview of civil courts, and then more egregious versions that are crimes. IMO, withholding significant pay that you have the ability to pay and is unambiguously contractually owed causes pretty serious harm, and society has strong reasons to criminalize this conduct.
Accepting services from someone while having no intent to honor the contract, hoping that disproportionate resources will prevent them from enforcing the contract "feels" like fraud: so let's codify it.